Heritabilities, Genetic Parameters, and Response to Selection in Pearl Millet × Elephantgrass Hexaploid Hybrids

Seeded pearl millet [Pennisetum glaucum (L.) R.Br.] × elephantgrass (Pennisetum purpureum Schum.) allohexaploids possess many desirable attributes for forage and biomass production. Estimation of genetic parameters would be useful in developing appropriate selection strategies. This study was conducted to obtain single-plant heritability estimates; genetic, phenotypic, and environmental correlations; and expected responses to selection for several vegetative and reproductive characteristics. Data were collected in 1990 and 1992 from a factorial experiment containing seven S₁ (selfed) families which were grown on a Sparr fine sand (sandy siliceous, hyperthermic Grossarenic Paleudult). Fewer plants were evaluated in 1992 because of lack of persistence. Due to significant year effects, and because 1992 data was affected by plant loss, years were analyzed separately. Heritability estimates differed among the 11 traits and were very low to moderate. Leaf width had the highest heritability for vegetative traits (0.16 in 1992). Heritabilities for reproductive characters were moderate in 1990, being highest for 100-seed weight (0.30) and seeds per panicle (0.29). In 1992, lack of significance among families for most reproductive characters reduced heritability estimates. Some correlations were consistent over years. Number of tillers was negatively associated genetically with plant height and leaf characteristics. Days to flowering was negatively associated with vegetative and reproductive traits. Seed-related traits were highly correlated among themselves. Despite moderate to low heritabilities for seed characters in 1990, expected responses to selection were high (17-43% increase) due to large phenotypic variation. For improving seed yield per plant, selecting indirectly for days to flowering or other seed-related traits would be more efficient. Improvement through phenotypic selection should be satisfactory in several traits. Florida Agric. Exp. Stn. Journal Series no. R-03486.