Combining abilities of certain characters and estimation of hybrid vigour in sunflower (Helianthus annuus L.)

Abstract

This research was carried out in 1997 and 1998 in order to study the genetic structure of a hybrid population established from three CMS (cytoplasmic male sterile) lines and four pollen tester (restorer) lines, to identify the parents and crosses showing superior general and specific combining abilities and finally to evaluate F1 hybrid vigour. According to the results, the variance due to specific combining ability (SCA) was highly significant for seed yield, number of seeds per head and plant height. These traits of sunflower were influenced, mostly, by dominant gene actions. Neither general (GCA) nor specific combining ability (SCA) variances were found to be significant for head diameter and 1000-seed weight. Most of the total genetic variation in these characteristics was caused by epistatic gene actions due to SCA variances, which were higher than GCA variances. The parental lines CMS381, CMS461, RHA684 and RHA892 had the highest positive GCA effects for seed yield and in terms of the other traits studied, but these effects were not significant for all the traits observed. The crosses CMS191×RHA723, CMS191×RHA892, CMS381×RHA684 and CMS461×RHA684 might be considered as promising combinations in terms of seed yield and yield components. The amounts of heterosis and heterobeltiosis ranged from -8.4 to +16.3% to -21.3 to +3.4% for plant height, from 46.3-82.3% to 20.3-48.3% for head diameter, from -14.8 to +52.6% to.-16.5 +46.9% for number of seeds per head, from -3.3 to +42.7 to -19.0 to +21.0% for 1000-seed weight and from 19.8-98.1 to 4.6-89.8%) for seed yield. © 2004 Akadémiai Kiadó, Budapest.