Data were collected from 218 commercial crops of vining peas (Pisum sativumcv. Dark Skinned Perfection) to test the hypothesis that variability between commercial crops in the yield of vining peas is associated with variation in the number of pods per plant. Yield varied widely between crops; the coefficient of variation of crop yield adjusted to tenderometer reading 105 was 25%. Only a small part of this variation could be accounted for by the correlation between yield and the estimated number of pods per plant (r = 0·067, 216 D.F.), and significance levels were not substantially improved by allowing for the effects of sowing date and plant density, or by using data on number of pods at each separate node in place of the overall totals per plant. Consequently the hypothesis stated above is not supported and it is suggested that variation in the weight of peas per pod was the main cause of variation in yield between crops.
A number of significant relationships were noted in the correlation analyses; (1) the mean number of pods per node at adjacent nodes tended to be positively correlated; (2) the number of pods per node at the first podding node tended to be positively correlated with plant density; (3) the numbers at the upper nodes tended to be negatively correlated with sowing date and with harvest date.