Line x tester analysis for plant height and head diametar in sunflower (Helianthus annuus)

Abstract

One of the prime tasks of sunflower breeding is the development of inbred lines by interspecific hybridization in order to obtain high-yielding and stable hybrids. This study used seven new divergent (A) CMS inbreds obtained by interspecific hybridization, three Rf restorer lines used as testers, and 21 F1 hybrids developed at the Institute of Field and Vegetable Crops in Novi Sad. A two-year trial with three replicates was set up at the Rimski Šancevi Experiment Field of the Institute of Field and Vegetable Crops using the line x tester method (Singh and Chouduary, 1976). Significant differences were found between the A-lines and Rf testers and their F1 hybrids in plant height and head diameter. Highly significant positive values of GCA for plant height and head diameter were found in the inbred lines NS-GS-4 and NSGS-5, whereas the inbred line NS-GS-1 had a highly significant negative GCA value. The greatest highly significant positive SCA value was found in NS-GS-6 x RHA-RPL-2/1 for plant height and in NS-GS-5 x RHA-R-PL-2/1 for head diameter. The nonadditive component of genetic variance played the main role in the inheritance of both plant height and head diameter, as shown by the ANOVA of variance of combining abilities and analysis of genetic variance components. This is supported by the GCA/SCA ratio for plant height (0.57) and head diameter (0.08) in the F1 generation, which was below the value of one for both traits and in both years of study. The largest average contribution in the expression of plant height (79.98%) and head diameter (55.56%) was that of the female A-lines. These results may be of importance for the development of new high-yielding sunflower genotypes based on interspecific hybridization.