GENETIC ANALYSIS AND EVALUATION OF SUN-FLOWER (Helianthus annuus L.) FOR MORPHO-PHYSIOLOGICAL AND BIOCHEMICAL CHARACTERISTICS

Abstract

The present research study was conducted during spring, 2003, 2004 and 200S at National Agricultural Research Centre, Islamabad, Pakistan. The purpose of the study was to develop more productive sunflower hybrids. The genetically diverse sunflower (Helianthus annuus L.) inbred lines comprising of six cytoplasmic male steriles (CMS) and six fertility restorers (Rr) were crossed in a line x tester mating design to obtain thirty six F, hybrids. The hybrids were evaluated for various quantitative traits including morpho-physiological traits, seed yield and yield related traits, protein content, oil content and quality traits. The mean values of parents and F, hybrids indicated a high genetic variation for all the traits under study. Sufficient genetic variability was observed among parents and F, hybrids as revealed by analysis of variance. An increased mean value among F, hybrids over parents was observed for plant height, stem diameter, number of leaves, leaf area, head diameter, yield per hectare, harvest index, moisture factor, oil content and oleic acid. A decrease in average mean value among F, hybrids over parents was observed for days to first flowering, days to 100 percent flowering, days to maturity, protein content, palmitic acid, stearic acid and linoleic acid. For the research year 2004, the highest heterotic value for yield per hectare was observed for cross combination, CMS-HSS-2-2-1 x C-206R while for 200S, it was recorded for CMS-303 x RHA-271. For oil content, the maximum heterosis was expressed by CMS-S3 x SF-187R and CMS-303 x RHA-29S during the research years 2004 and 200S, respectively. The F, hybrid, CMS-HSS-2-2-1 x SF-187R exhibited the desirable negative heterotic value for stearic acid during the research years 2004 and 200S. A highly significant desirable heterotic value for oleic acid during 2004 and 200S was recorded for CMS-HSS-2-2-1 x RHA-29S. The line x tester analysis of general combining ability was conducted for all the characters under study. Among parents, the females, CMS-HSS-2-2-1 and CMS-303 while the males, C-206R and RHA-271 are the best general combiners for seed yield per hectare. The F, hybrids, CMS-HSS-2-2-1 x C-206R and CMS-303 x RHA-271 are the potential crosses with desirable SCA estimates for yield per hectare. For oil content, the female parents, CMS-S3 and CMS-HSS-2-2-1, whereas the male parents, RHA-29S and PAC-8712 proved to be the potential parents exhibiting desirable positive GCA magnitudes. The F\ hybrids CMS-53 x SF-187R and CMS-303 x RHA-295 are the potential crosses for oil content. For the years 2004 and 2005, the specific combining ability variances for all characters were higher than general combining ability variances, showing non-additive type of gene action controlling the characters. Non-additive type of gene action can be utilized for varietal improvement through heterosis breeding. Simple correlation studies exhibited strong association among parents and crosses for all the characters under investigation. For 2004, among parents, seed yield per hectare was correlated positively and significantly with leaf area, head diameter and 1000-seed weight. Among crosses, the character was positively and significantly associated with head diameter and lOOO-seed weight. For 2005, among parents, seed yield per hectare was positively and highly significantly correlated with harvest index and moisture factor. A positive and significant correlation existed for head diameter and 1000-seed weight. Among crosses, seed yield was correlated positively highly significantly with harvest index and 1000-seed weight while a positive non-significant correlation was observed for leaf area, head diameter and moisture factor. For 2004, oil content among parents, was positively and non-significantly correlated for all seed yield and related characters. For 2005, a positive and highly significant correlation existed between oil content and linoleic acid. Among crosses, a positive and highly significant correlation for oil content was observed with protein content and oleic acid in 2004 and linoleic acid in 2005. Correlation studies are helpful in selection for high seed yield, seed oil content or other desirable characteristics for breeding sunflower.