INHERITANCE OF VEGETATIVE GROWTH INDEX AND RELATED TRAITS IN PEARL-MILLET

Growth index (GI) is a measure of plant dry weight produced per unit o f land area per day (grams per square meter per day). The objective of this study was to elucidate the inheritance pattern of GI for pearl m illet [Pennisetum glaucum (L.) R. Br.]. A generation means analysis wa s conducted to determine the relative importance of additive, dominanc e, heterotic, and additive x additive epistatic genetic effects for GI . Two elite open-pollinated and three landrace varieties of pearl mill et were mated, and the parents, parents selfed, F(1)s, F(1)s selfed, a nd F(1)s random mated were evaluated in 1990 and 1991 at the Internati onal Crops Research Institute for the Semi-Arid Tropics, near Hyderaba d, India. Traits measured were GI at 10 d after bloom date (GI1) and a t maturity (GI2), bloom date, biomass, harvest index, and plant height . The fully fitted genetic model for the generation means explained fr om 88 to 95% of the variation among the generations sum of squares for the various traits. Additive effects accounted for the largest propor tion of the variation among generation means for all traits except GI2 and biomass, where additive x additive epistatic effects were of grea test importance. Even though inheritance patterns for GI1 and GI2 were dissimilar, a breeding method that emphasizes selection for additive genetic effects should be suitable for improving them.