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The accumulation of nutrients during diapause preparation is crucial because any lack of nutrition will reduce the likelihood of insects completing diapause, thereby decreasing their chances of survival and reproduction. The fall webworm, Hyphantria cunea, diapause as overwintering pupae and their diapause incidence and diapause intensity are regulated by the photoperiod. In this study, we test the hypothesis that photoperiod influences energy reserve accumulation during diapause preparation in fall webworm. We found that the body size and mass, lipid and carbohydrate content of pupae with a short photoperiod during the diapause induction phase were significantly greater than those of pupae with a relatively short photoperiod, and the efficiency of converting digested food and ingested food into body matter was greater in the short-photoperiod diapause-destined larvae than the relatively short-photoperiod diapause-destined larvae. We also observed higher lipase and amylase activities in short-photoperiod diapause-destined larvae relative to the counterparts. However, no obvious difference was found in protein and protease in the pupae with a short photoperiod during the diapause induction phase and short-photoperiod diapause-destined larvae compared with the counterparts. Therefore, we conclude that the energy reserve patterns of diapausing fall webworm pupae are plastic and that short-photoperiod diapause-destined larvae increase their energy reserves by improving their feeding efficiency and increase their lipid and carbohydrate stores by increasing the lipase and amylase activities in the midgut.
Redroot pigweed (Amaranthus retroflexus L.) and slender amaranth (Amaranthus viridis L.) are considered emerging problematic weeds in summer crops in Australia. An outdoor pot experiment was conducted to examine the effects of planting time on two populations of A. retroflexus and A. viridis at the research farm of the University of Queensland, Australia. Both species were planted every month from October to January (2017 to 2018 and 2018 to 2019), and their growth and seed production were recorded. Although both weeds matured at a similar number of growing degree days (GDD), they required a different number of days to complete their life cycles depending on planting date. The growth period was reduced and flowering occurred sooner as both species experienced cooler temperatures and shorter daylight hours. Both species exhibited increased height, biomass, and seed production for the October-sown plants compared with other planting times, and these parameters were reduced by delaying the planting time. The shoot and root biomass of A. retroflexus and A. viridis (averaged over both populations) was reduced by more than 70% and 65%, respectively, when planted in January, in comparison to planting in October. When planted in October, A. retroflexus and A. viridis produced 11,350 and 5,780 seeds plant−1, but these were reduced to 770 and 365 seeds plant−1 for the January planting date, respectively. Although the growth and fecundity of these species were dependent on planting time, these weeds could emerge throughout the late spring to summer growing season (October to March) in southeast Australia and could produce a significant number of seeds. The results showed that when these species emerged in the late spring (October), they grew vigorously and produced more biomass in comparison with the other planting dates. Therefore, any early weed management practice for these species could be beneficial for minimizing the subsequent cost and energy inputs toward their control.
The prediction of the post-diapause emergence is the first step towards a comprehensive decision support system that can contribute to a considerable reduction of pesticide use by forecasting a precise spraying date. The cumulative field emergence can be described as a function of the cumulative development rate. We investigated the impact of seven constant temperatures and five light regimes on post-diapause development in laboratory experiments. Development rate depended significantly on temperature but not on photoperiod. We therefore fit non-linear thermal performance curves, a better and more modern approach over past linear models, to describe the development rate as a function of temperature. The four parameter Brière function was the most suitable and was subsequently applied to temperature data from 36 previous pea fields, where pea moth emergence was measured with pheromone traps in Northern Hesse (Germany). In order to describe the variation in development times between individuals, we fit five nonlinear distribution models to the cumulative development rate as a function of cumulative field emergence. The three parameter Gompertz model was selected as the best fitted model. We validated the model performance with an independent field data set. The model correctly predicted the first moth in the trap and the peak emergence in 81.82% of cases, with an average deviation of only 2.00 and 2.09 days respectively.
Recruitment is related to the occupation of the substrate by fouling organisms. It plays an important role in the maintenance and distribution of benthic populations, being under the influence of biotic and abiotic factors. In the present work, the recruitment of calcareous sponges was monitored over two years in a marina at Todos os Santos Bay, a large bay in the tropical portion of the Brazilian coast. Artificial plates were immersed, being replaced bimonthly and the potential influence of the seawater temperature, photoperiod and precipitation on the number of sponge recruits was tested. The results showed that the number of calcareous sponge recruits had significant temporal variation. Nevertheless, different species showed different patterns over time. Significant differences were observed for Sycon avus, Sycon sp. and Leucandra serrata, and the periods with the highest number of recruits were different amongst them. Sycon bellum, Paraleucilla incomposita, Leucilla sp. and Heteropia glomerosa did not show significant variation in the number of recruits over time. None of the three tested environmental factors were correlated with the number of recruits, but results indicated S. avus recruitment might be driven by seawater temperature. Our results contribute to improve the current knowledge on the dynamics of each species found on the plates and reinforce the general view that the pattern of recruitment varies greatly in Calcarea, even amongst sympatric species.
In semiarid conditions, feed is often scarce and variable with underfeeding being common; these factors can potentially induce fertility reductions in both sexes. Sexually active bucks are able to very efficiently fertilize out-of-season goats, but we do not know whether underfeeding would reduce the ability of bucks to fertilize goats during these periods. Two experiments were conducted to determine (i) testicular size and change of odor intensity of undernourished bucks exposed to long days and (ii) the ability of these bucks to stimulate reproductive activity in seasonally anestrous goats. In experiment 1, bucks (n = 7) were fed 1.5 times the normal maintenance requirements from September to May and formed the well-fed group. Another group of bucks (n = 7) were fed 0.5 times the maintenance requirements and formed the undernourished group. All bucks were subjected to artificially long days from 1 November to 15 January; this period was followed by a natural photoperiod until 30 May. Body weight, scrotal circumference and male odor intensity changes were determined every 2 weeks. In experiment 2, two groups of female goats (n = 26 each) were exposed to well-fed (n = 2) or undernourished bucks (n = 2) on 31 March. Ovulations and pregnancy rates were determined by transrectal ultrasonography. In experiment 1, a treatment by time interaction was detected for BW, scrotal circumference and odor intensity changes (P < 0.001). The BWs of well-fed bucks were greater than those of the undernourished bucks from October to May (P < 0.01), as were the scrotal circumferences from December to March (P < 0.05) and odor intensities from February to May (P < 0.05). In experiment 2, the proportions of females that ovulated at least once (100% v. 96%) or those that were diagnosed as pregnant (85% v. 77%; P > 0.05) did not differ significantly between the goats exposed to well-fed or undernourished bucks. The interval between the introduction of bucks and the onset of estrous behavior was shorter in goats exposed to well-fed bucks compared to the interval for those goats exposed to undernourished bucks (2.5 ± 0.2 v. 9.5 ± 0.6 days; P < 0.05). We conclude that undernourishment reduces the testicular size and odor intensity responses in bucks exposed to long days, but that undernourished bucks are still able to stimulate reproductive activity in seasonally anestrous goats, as is also the case for well-fed bucks.
The effect of month of birth on personality traits was investigated in 595 healthy Japanese. Personality traits were evaluated by the Temperament and Character Inventory (TCI). Statistical analyses were conducted in two steps. Firstly, months of the year were divided according to ambient temperature or photoperiod, and TCI scores were compared between month groups by analysis of covariance (ANCOVA) with age as a covariate. Secondly, multiple regression analysis was performed with TCI scores as dependent variables and ambient temperature and photoperiod at birth month and age as independent variables. Both analyses showed that higher ambient temperature at birth month was related to higher scores of self-directedness and persistence in females. Also, higher ambient temperature at birth month was related to lower body mass index (BMI) in females. These results suggest that month of birth affects self-directedness and persistence in healthy Japanese females, and these effects may be mediated by BMI changes associated with ambient temperature at birth month.
The effect of five photoperiods (0:24, 6:18; 12:12, 18:6, and 24:0 light:dark (L:D)) on the development, reproduction, and survival of the predatory thrips Scolothrips longicornis Priesner fed on the two-spotted spider mite, Tetranychus urticae Koch, was tested under laboratory conditions at 60% RH and 25°C. Development time of almost all immature stages in S. longicornis was the shortest under long day lengths (18:6 and 24:0 L:D). The adult duration of both sexes decreased with increasing light length from 6 to 24 h. The longevity of male and female decreased with increasing light length. Under a 12:12 L:D photoperiod, S. longicornis females had the longest oviposition period and longevity, highest net reproductive rate (R0 = 15.37), intrinsic rate of natural increase (r = 0.141), and finite rate of increase (λ = 1.151). Life table parameters showed a significant difference with various photoperiods. The consequences of the present research demonstrated that a 12:12 L:D photoperiod is the most favorable for the reproduction and development of S. longicornis fed on T. urticae, and that for mas rearing for augmentative biological control programs, would be the ideal photoperiod to maximize production.
This research communication addresses the hypothesis that in dual-purpose goats, exposure to 1 h of extra-light given from 16 to 17 h after dawn (pulse of light) in winter stimulates milk yield. One group of goats was maintained under natural short photoperiod (natural day; ND (n = 7)). Another group of lactating females was submitted to an artificial long-day photoperiod consisting of 16 h light and 8 h darkness (long days; LD (n = 7)). A third group of females received one single hour of extra-light 16 h after the fixed dawn (pulse of light; PL (n = 6)). Goats from LD and PL yielded 30% more milk than goats from ND. Mean percentages of fat, protein and lactose contents in milk did not differ between the 3 groups at any stage of lactation, but these components in grams/day were higher in goats from PL than in the others two groups within the first 45 d of lactation. In conclusion, dual-purpose lactating goats that started their lactation during natural short days, the daily exposition to a 1-h pulse of light is sufficient to stimulate milk yield compared to females maintained under natural short photoperiod.
The intensive production system for broiler chicken is characterised by the provision of a suitable micro-climatic condition such as temperature, airflow, relative humidity and light for proper bird's management which always, together with appropriate feeding and nutrition, favours the full growth and production potentials of the birds. Lighting, amongst other factors, is a potent and critical micro-climatic component in broiler houses as it influences many behavioural, physiological and metabolic processes in birds. To optimise the intensive system for broiler production, various lighting programmes (regarding light duration and its distribution, light colour/wavelength and light intensity) have been explored. This review compares the effects of different elements of lighting regimen on the growth performance, health, and welfare and carcass characteristics of broilers. Considering this, various degrees of intermittent photo-period (i.e. mixing photo- and scoto- periods within 24 hours) rather than one continuous photoperiod have been proven to significantly improve broilers’ weight gain by 3.4-5.8%, feed to gain ratio up to 7.3%, mobility up to 46.5%, decrease mortality rate ranging between 0.43% and 0.72%, and finally, increase carcass yield. Short wavelength lights and light intensity of ≥5 lux after the initial brooding period are said to stimulate birds’ metabolism and growth thereby, enhancing the production system. In conclusion, the lighting programme, apart from improving broiler productivity, could reduce cost expended on energy in an intensive production system.
Environmental characteristics (for example, temperature, photoperiod) as seasonal cues can affect the offspring sex ratio and reproductive tactics of many hymenopteran insects. Leptocybe invasa Fisher & La Salle is the most critical invasive insect pest of Eucalyptus spp. in the world and displays thelytokous reproduction. In the current study, we studied the effects of temperature and photoperiod on offspring sex ratio and reproductive tactics in L. invasa. Results show that sex ratio (female: male) of L. invasa was under 15, 25 and 35 °C with both L 12: D 12 and L 16: D 8, and cold and thermal acclimation were 74.5:1, 71.0:1, 59.0:0, 17.3:1, 53.0:0, 64.0:0, 47.0:1 and 56.0:0, respectively, which was highly significantly female biased and with no significant difference due to temperature or photoperiod. Offspring virgin females oviposited and induced the bump-shaped galls on plants under the same conditions as described above. Constant temperature, photoperiod and their interaction, and cold and thermal acclimation had no significant effect on the infestation rates of Eucalyptus branches induced by offspring virgin females. Thus, temperature, photoperiod and cold and thermal acclimation did not influence female-biased sex ratio and tactics with thelytokous reproduction of offspring females in L. invasa.
The Deleted in AZoospermia (DAZ) gene family regulates the development, maturation and maintenance of germ cells and spermatogenesis in mammals. The DAZ family consists of two autosomal genes, Boule and Dazl (Daz-like), and the Daz gene on chromosome Y. The aim of this study was to analyze the localization of DAZL and BOULE during testicular ontogeny of the seasonal-breeding Syrian hamster, Mesocricetus auratus. We also evaluated the testicular expression of DAZ family genes under short- or long-photoperiod conditions. In the pre-pubertal and adult testis, DAZL protein was found mainly in spermatogonia. BOULE was found in the spermatogonia from 20 days of age and during the pre-pubertal and adult period it was also detected in spermatocytes and round spermatids. DAZL and BOULE expression in spermatogonia was strictly nuclear only in 20-day-old hamsters. We also detected the novel mRNA and protein expression of BOULE in Leydig cells. In adult hamsters, Dazl expression was increased in regressed testis compared with non-regressed testis and DAZL protein expression was restricted to primary spermatocytes in regressed testis. These results show that DAZL and BOULE are expressed in spermatogonia at early stages in the Syrian hamster, then both proteins translocate to the cytoplasm when meiosis starts. In the adult regressed testis, the absence of DAZL in spermatogonia might be related to the decrease in germ cell number, suggesting that DAZ gene family expression is involved in changes in seminiferous epithelium during photoregression.
Increasing evidence has demonstrated that the environmental conditions experienced by parents can shape offspring phenotypes. Here, we examined the effects of the photoperiod and temperature experienced by parents on the incidence of diapause in their progeny in the cabbage beetle, Colaphellus bowringi, using three experiments. The first experiment examined parental diapause incidence under different photoperiods at 25°C and the incidence of diapause in progeny from both non-diapausing and diapausing parents under the same rearing conditions. The results revealed that the incidence of diapause among progeny was exactly opposite to that of their parents, i.e., higher parental diapause incidence led to lower progeny diapause incidence, showing a negative relationship in diapause incidence between the parental generation and the progeny generation. The incidence of diapause among progeny produced by diapausing parents was higher than that in progeny produced by non-diapausing parents. The second experiment examined parental diapause incidence at different temperatures under LD 12:12 and the incidence of diapause in progeny from both non-diapausing and diapausing parents under the same rearing conditions. Similarly, the incidence of diapause in progeny was also opposite to that of their parents. However, the incidence of diapause in progeny produced by non-diapausing parents was different from that in progeny produced by diapausing parents. In the third experiment, naturally diapausing adults were maintained at a constant temperature of 9, 28°C or the mean daily summer temperature of 27.84°C under continuous darkness for 3 months of dormancy. After dormancy, the progeny of these post-diapause parents were reared under different photoperiods at 25°C. The results showed that the incidence of diapause among progeny was higher when their parents experienced high temperatures than when they experienced low temperatures. All results demonstrate that the photoperiod and temperature experienced by parents may significantly affect the diapause incidence among progeny.
Temporal variations over short and medium time scales play an important role in fish assemblage dynamics, but have been poorly investigated in tropical estuaries. This study evaluates the hypothesis that fishes co-occurring on a tidal mudflat have different patterns of temporal segregation at short- and medium-term scales that optimize resource use and habitat partitioning. A total of 6222 individuals and 66 fish species were caught during different hours covering the entire 24 h cycle, tidal regimes and the wet and dry seasons. Biomass and species richness, and to a lesser extent CPUE and evenness, showed statistically significant interactions across short- and medium-term scales. Biomass was higher during the dry season and its oscillation along tidal cycles revealed distinct patterns over the photoperiod in each season. A similar complex pattern was also observed for species richness, which showed distinct temporal patterns between high and low tides over the photoperiod in each season. Overall, shorter-term variations on fish assemblage attributes were correlated mainly with photoperiod and, to a lesser extent, tidal regime. Medium-term variations in fish abundance and species richness, in contrast, could result from seasonality in recruitment patterns and higher availability of allochthonous food resources during the wet period.
Waterhemp is a weed indigenous to the midwestern United States and is problematic in agronomic crop production. This weed is well suited to inhabit minimally tilled environments and is increasing in prevalence across many agricultural production areas and systems. A common garden experiment was established in Indiana in 2014 and 2015 with waterhemp populations from Indiana, Illinois, Missouri, Iowa, and Nebraska to compare the growth and development of waterhemp from these regions. Three establishment dates (May, June, and July) were used each year to simulate discontinuous germination. Mean biomass accumulations from the May (1,120 g plant−1) and June (1,069 g plant−1) establishment dates were higher than from the July (266 g plant−1) establishment date. There were no differences in biomass accumulations between the five populations in the May and June establishments, but biomass accumulations ranged from 195 to 338 g plant−1 in the July establishment. Mean seed yields were higher from the May (926,629 seeds plant−1) and June (828,905 seeds plant−1) establishment dates compared with the July (276,258 seeds plant−1) establishment. In the May and June establishments, seed yields ranged from 469,939 seeds plant−1 to 1,285,556 seeds plant−1. The Illinois population flowered the latest of all the populations yet also grew the tallest. The July establishment flowered the most rapidly after establishment, accumulated less biomass, and also had the largest seeds. This study demonstrated differences among waterhemp populations when grown in a common environment and the effect of establishment timing on waterhemp growth and development.
Seasonal reproduction is one of the major biotechnical and economic constraints of sheep production in temperate latitudes. Treatments using extra light followed by melatonin implants have been used satisfactorily in open barns, farms and artificial insemination centres to produce out-of-season sexual activity in rams. The aim of the present study is to explore the possibility of replacing melatonin implants with continuous light (LL), which was recently shown to increase LH secretion similar to melatonin and/or pinealectomy. Four experiments during 4 consecutive years were conducted in ‘Ile-de-France’ rams. In each study, one group was systematically exposed to permanent light after a first photoperiodic treatment of 60 long days (LD-LL) during the winter and compared with various other control groups subjected either to a natural photoperiod or the classical LD-melatonin treatment. As expected, blood nocturnal melatonin secretion was suppressed by LL. In all four experiments, LL treatment produced a highly significant and robust increase in ram testicular volume in the spring compared with the testicular volume of control rams or of that of treated rams at the end of the LD. For the two experiments in which fertility was tested, fertility after hand-mating was significantly higher in LD-LL rams than in control rams (76% v. 64%). Therefore, permanent light after an LD treatment may be an interesting alternative to LD-melatonin treatment to induce out-of-season sexual activity in rams.
The Asian tiger mosquito, Aedes albopictus (Skuse) and the yellow fever mosquito, Aedes aegypti (Linnaeus) are medically important species that vector several arboviruses. Globally, populations of both species experience (and are sensitive to) photoperiodic variations. The present study aims to test if photoperiod regimes affect the population performance of Ae. albopictus and Ae. aegypti. Since mosquitoes have sex-specific strategies to maximize fitness, we also tested the hypothesis that Ae. albopictus and Ae. aegypti would exhibit differences in the male and female response (sexually dimorphic response) to various photoperiod treatments. We reared cohorts of first instar larvae to adulthood in three photoperiod treatments: short day (10 h light), control (12 h light) and long day (14 h light). We measured and compared survival to adulthood, population growth, development time of males and females, and wing length across treatments. Although we detected no effects of photoperiod on the population performance of both species, we found evidence of a sexual dimorphic response to photoperiod in Ae. albopictus, but not in Ae. aegypti, with Ae. albopictus females being more sensitive to variations in photoperiod. The observed differences between sexes of Ae. albopictus are consistent with sex-specific developmental constraints. The absence of a sexually dimorphic response to photoperiod in Ae. aegypti can be attributed to different strategies evolved in this species to prepare for unfavourable conditions associated with shorter day length. We discuss the ecological and medical implications of our findings.
In rams, artificial long days followed by continuous light stimulate testosterone secretion during the non-breeding season. The objective of this study was to determine whether artificial long days followed by continuous light could stimulate testosterone secretion in Alpine bucks as well as in those exposed to long days followed by a melatonin treatment. All bucks were kept in shaded open pens. Control males were exposed to natural photoperiod conditions (n=5). Males of the two experimental groups were exposed to 2.5 months of long days from 1 December (n=5 each). On 16 February, one group of males was exposed to 24 h of light per day until 30 June; the other group was exposed to natural variations of photoperiod and received two s.c. melatonin implants. Testicular weight was determined every 2 weeks, and the plasma testosterone concentrations once a week. In the control and the two photoperiodic-treated groups, a treatment×time interaction was detected for testicular weight and plasma testosterone concentrations (P<0.001). In control bucks, testicular weight increased from January and peaked in June, whereas in both photoperiodic-treated groups, this variable increased from January, but peaked in April, when the values were higher than in controls (P<0.05). In the control group, plasma testosterone concentrations remained low from January to June, whereas in both photoperiodic-treated groups, this variable remained low from January to March; thereafter, these levels increased in both photoperiodic-treated groups, and were higher than controls in April and May (P<0.05). We conclude that continuous light after a long-day treatment stimulate testosterone secretion in Alpine male goats during the non-breeding season as well as the long days followed by a melatonin treatment. Therefore, continuous light could replace the implants of melatonin.
The intensity of pupal diapause in the cotton bollworm, Helicoverpa armigera (Hübner) was investigated under both laboratory and natural conditions. By transferring diapausing pupae induced under LD 11:13, LD 12:12 and LD 13:11 at 20, 22 and 25 °C to 25 °C combined with LD 15:9 to terminate diapause the rearing day length of 11 h evoked greater intensity of diapause than did 12 and 13 h at 25 °C; whereas the rearing temperature of 25 °C evoked more intense diapause than did 20 and 22 °C under LD 11:13. By transferring diapausing pupae induced under LD 12:12 at 20 and 22 °C to six temperatures of 18, 20, 22, 25, 28 and 31 °C combined with LD 15:9 to terminate diapause, the duration of diapause was significantly shortened from 146 days at 18 °C to 24 days at 31 °C, showing that high temperatures significantly accelerate diapause development. Furthermore, the duration of diapause was significantly longer at the rearing temperature of 22 °C than that at 20 °C when the diapause-terminating temperatures were 20 and 22 °C. Chilling at 5 °C did not shorten the duration of diapause but lengthened it when chilling period was included. However, chilling plays an important role in synchronizing adult emergence. Rearing temperature of 22 °C also evoked more intense diapause than did 20 °C in most chilling treatments. When the overwintering pupae were transferred at different times from natural temperatures to 25 °C, it was found that the earlier the transfer took place, the earlier the adults emerged when the time spent under natural conditions was included. However, cool temperatures before March showed an enhanced effect on diapause development at 20 °C, suggesting that the high diapause-terminating temperature can offset the effect of chilling on diapause development. The result of diapause termination under natural conditions suggests that the developmental threshold for post-diapause development in H. armigera should be around 17.5 °C.
Tall morningglory is an annual broadleaf vine and a problem weed in many
annual and perennial crops in several countries including the United States.
A better understanding of the germination biology of tall morningglory would
facilitate the development of better control strategies for this weed.
Experiments were conducted under greenhouse and laboratory conditions to
evaluate the effects of various environmental factors, such as temperature,
light, planting depth, pH, osmotic and salt stress, and flooding duration,
on the germination of tall morningglory. The results suggested that the
optimum day/night temperature range for the germination of tall morningglory
was 20/12.5 to 35/25 C and maximum germination (89%) was observed at 30/20
C. Temperature higher and lower than the optimum range significantly reduced
germination. Alternate light and dark did not have any adverse effect on the
germination of tall morningglory seeds. The germination was 10% at an
osmotic stress of −0.3 and −0.4 MPa, and above that, no germination was
observed. Tall morningglory showed some tolerance to salt stress. The
germination was 40% and 12% at salt concentrations of 50 mM and 200 mM,
respectively. Germination was affected by pH levels, and maximum germination
occurred at pH 6, whereas above or below that level, germination was
significantly reduced. Maximum germination of seeds was 83 and 94% when sown
at 0 and 2 cm depth in soil, within a week of sowing; however, germination
was significantly reduced to 76% when placed at a depth of 4 cm or deeper.
Under no flooding treatment, 87% of seed germinated, but flooding delayed
and inhibited the germination of tall morningglory seeds. It is concluded
that several environmental factors affected the germination of tall
morningglory, and this information could help to predict the spread of tall
morningglory in new areas such as Florida.
The ICRISAT genebank, Patancheru, India holds 22,211 pearl millet germplasm accessions from 50 countries, including 19,063 landraces. Among these, 15,904 landraces that were geo-referenced are either thermo-sensitive (52.5%), or photoperiod-sensitive (45.6%), or insensitive to both temperature and photoperiod (2%). Latitude ranges of 10–15°N with 39.6% and 15–20°S with 13.1% of total accessions are the important regions for pearl millet germplasm. A study on climate data of the germplasm collection sites revealed that most accessions from latitudes ranging from 10 to 20° on both sides of the equator were highly sensitive to longer photoperiod (>12.5 h) and/or lower temperature ( < 12°C). Accessions that originated in locations at higher latitudes (>20–35°) on both the hemispheres exhibited low sensitivity to both photoperiod and low temperature, as they were exposed to such climates during their evolution. The accessions that are insensitive to both photoperiod and temperature were few but they originated from locations spread across all latitudes, although the highest numbers were from mid-latitudes (15–20°) in both hemispheres. As germplasm accessions are sensitive to climatic variables such as temperature and photoperiod, recording of location-specific geo-reference data while collecting the germplasm, which can help to elucidate the sensitivity of accessions to temperature and photoperiod, is emphasized. Critical evaluation of photoperiod-sensitive accessions that are late flowering for forage production and the photoperiod-insensitive early-maturing accessions for grain production, multiple cropping and development of parental lines with synchronized flowering for the development of hybrids is suggested.