| dc.description | Mean seed weight (MSW) is a relevant trait in grass pea (Lathyrus sativus L.) commercialization because large grains are preferred in Western markets. Extending the knowledge on its mode of inheritance among large-seeded types would be useful in breeding programs, and therefore it was the objective of this work. A broad range of MSW is found in grass pea, starting at about 30 mg. Three lines (LS-97, LS-8, and LS-2026) within the large-seeded group but with significantly different MSW (179, 360 and 470 mg, respectively), were crossed in a complete diallel. Part of the F1 seed was sown and the remainder was stored. F1 plants from each cross were allowed to produce F2 seed and some were backcrossed to their respective parents. Parents, F1, F2, and backcross populations were grown in the field in 2006. MSW was obtained from single plants in each population. No difference was observed between reciprocals of crosses LS-97 ’ LS-8 and LS-8 ’ LS-2026; therefore, data from reciprocals were combined, assuming nuclear inheritance. However, F2 segregating population from cross LS-97 ’ LS-2026 and its reciprocal gave significantly different means, suggesting cytoplasmic inheritance. Consequently, F2 and backcross data were handled separately to calculate heritability. Parent lines with high MSW, particularly LS-2026, had greater variances, raising the estimate of environmental variance. Broad sense heritability estimates for MSW were 0.50 and 0.32 for crosses LS-97 ’ LS-8 and LS-8 ’ LS-2026, respectively, and 0.23 and 0.24, for cross LS-97 ’ LS-2026 and its reciprocal, respectively. Narrow sense heritabilities were 0.42 and 0.28, and 0.15 and 0.22, respectively. In all crosses, the genetic effects were predominantly additive, predicting a good response to selection for increased MSW in early segregating generations. Thus, the prospects to improve MSW in large-seeded grass peas are auspicious. | |
