Combining ability and heterosis in Sorgum (Sorghum bicolor L.)

Abstract

For the sustainable improvement of sorghum (Sorghum bicolor L.), local genotypes were conventionally crossed in East Java, Indonesia to determine a) the crossing success of different genotypes, b) germination percentage and seed setting traits, and c) the combining ability and heterotic effect of sorghum parental genotypes and their F1 diallel hybrids. Three sorghum genotypes (‘Lamongan-1’, ‘Tulungagung-2’, and ‘Jombang’) from the local germplasm were collected from various regions in East Java, Indonesia, and were crossed in a complete diallel design. The experiment was carried out in a randomized complete block design with four replications during 2018–2019 at the Agrotechnology Laboratory, Faculty of Agriculture, University of Muhammadiyah, Malang, Indonesia. Results showed that the parental genotypes and their F1 hybrids exhibited significant differences in seed weight and seed diameter and nonsignificant differences in germination percentage and seed setting. The parental genotype ‘Tulungagung-2’ and its hybrids ‘Jombang’ × ‘Tulungagung-2’, ‘Tulungagung-2’ × ‘Lamongan-1’, and ‘Jombang’ × ‘Tulungagung-2’ presented the highest germination percentages, seed setting, seed weights, and seed diameters. The genotype ‘Tulungagung-2’ had the highest general combining ability and was identified as a good general paternal and maternal parent for the production of promising F1 hybrids. The hybrid ‘Jombang’ × ‘Lamongan-1’ had the highest specific combining ability for all of the characters and was recognized as a promising F1 hybrid for improving sorghum yield. Cluster analysis divided all of the parental genotypes and their F1 hybrids into two large groups with a similarity of 13.13%.