Inheritance of Vegetative Growth Index and Related Traits in Pearl Millet
1995
Lynch, P. J. | Rattunde, E. W. | Frey, K. J.
Growth index (GI) is a measure of plant dry weight produced per unit of 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 millet [Pennisetum glaucum (L.) R. Br.]. A generation means analysis was conducted to determine the relative importance of additive, dominance, heterotic, and additive × additive epistatic genetic effects for GI. Two elite open-pollinated and three landrace varieties of pearl millet were mated, and the parents, parent selfed, F₁s, F₁s selfed, and F₁s randomated were evaluated in 1990 and 1991 at the International Crops Research Institute for the Semi-Arid Tropics, near Hyderabad, India. Traits measured were GI at 10 d after bloom date (GI1) and at maturity (GI2), bloom date, biomass, harvest index, and plant height. The fully fitted genetic model for the generation means explained from 88 to 95% of the variation among the generations sum of squares for the various traits. Additive effects accounted for the largest proportion of the variation among generation means for all traits except GI2 and biomass, where additive × additive epistatic effects were of greatest 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. Joint contribution from the Dep. of Agronomy, Iowa State Univ. Journal Paper no. J-15414 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, IA 50011, Project no. 2447 and Journal Article no. JA-1561 of ICRISAT. Part of a dissertation submitted by P.J. Lynch in partial fulfillment of the requirements for the Ph.D. degree.
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