ESTIMATION OF THE ADDITIVE VARIANCE AND HERITABILITY IN TWO POPULATIONS OF HUSK TOMATO (Physalis ixocarpa Brot.)

Abstract

The objective of this paper was to study the change in the additive variance and heritability of weight (yield) and number of fruits of the variety of husk tomato (Physalis ixocarpa Brot.) Rendidora after six cycles of selection. Estimations were based on the method
of maternal half sibs. After six cycles of selection the yield underwent a statistically significant increase of 300 g/plant, with selection cycle^-1 gain of about 9.08 %. This increase must be related to a change of the frequency of desirable genes, evidenced by a change in the estimate of the coefficient of the additive variance from 37.05 % to 17.42 %. For fruit number, the change was from 42.66 % to 16.43 %. This general results are consistent with a situation of a high proportion of additive gene action and a gene frequency of at least 0.5, although some other models could be compatible with these data. Narrow sense heritability on a mean basis estimates for yield and fruit number were 0.65 and 0.51, respectively, for Rendidora and 0.23 and 0.26 for the improved population. The superiority of the estimates for Rendidora is consistent with the observed estimates for the additive variance.