Soyabeans in Tanzania: II. Seasonal variation and homeostasis in soyabeans

Abstract

1. Investigations of individual soyabean families over a 5-year period showed in some famines that the strain compounded in theF5generation had a more stable environment × genotype interaction than the daughter strains compounded in theF6generation.2. Regression of each strain yield on an ‘environmental’ mean gave values for the slope of the regression line (bi), and the mean square of the regression (s2d) gave a value of deviations from the regression line. The valuesbiands2dwere used as estimates of stability.3. Groups ofF5andF6compounded strains were compared. Analysis of variance for yield over 5 years for twenty-fourF5compounded strains and twentyfourF6compounded strains gaves2dvalue of 166·4 for the former and 289·1 for the latter. With 72 degrees of freedom for each group they differed from each other at the 1 % level ofP.4. Multiple correlation analyses were also done on the two groups of strains. It was concluded, all else being equal, that theF5strains over a period of years would be less liable to give low yields in a bad year than theF6strains.