Syed, Waseem Hasan (2001) HERITABILITY ESTIMATES, GENETIC CORRELATIONS AND PREDICTED GAINS FROM S1 FAMILIES IN TWO RANDOM MATED SUNFLOWER POPULATIONS. PhD thesis, University of the Punjab, Lahore.
No doubt researchers have been striving and investigating the genetics of different characters of sunflower plant, working with various populations, varieties, hybrids and lines. The aim of this study was to review the finding of earlier workers and undertake to collect information about two random mated sunflower populations (Local open and UAF comprised of local and exotic germplasm, respectively) under diverse environmental conditions of spring and autumn seasons. For this purpose, estimates of mean, range, coefficient of variability, correlation (genetics and phenotypic) , genetic gain and correlated response for twelve agronomic traits were obtained in improving the seed yield and oil yield, which is the ultimate objective of any breeding program. It is evident from the magnitudes of mean, range and coefficients of variation, that both the sunflower populations ( Local open and UAF) seemed to have larger variability for all traits under investigation and are exploitable during both seasons ( Spring and Autumn). A comparison among S1 families from both local open and UAF exhibited almost similar and larger mean values for all traits ( number of leaves per plant, days to flowering, days to anthesis, days to maturity, plant height (cm), number of achenes per head, 100 achene weight ( g ), seed yield plant ( g ), seed yield per acre (kg/Acre), oil content (%) and oil yield per acre (kg / Acre ) , except head diameter during spring than autumn. The prevailing environment during spring seemed to be favorable and resulted in higher estimates of seed yield and its components. In general, yield and its components showed larger values of coefficients of variation in both sunflower populations during both season. The results demonstrated highly significant difference among S1families for all traits except number of leaves per plant ( spring season ) in UAF and ( Autumn season ) in Local open sunflower populations. Error variances for environments of autumn. Similarly, there was an increase in local open as compared to UAF population. The S1 family genetic variance decreased in local open population for days to maturity, seed yield per acre ( spring ) and for all traits except days to maturity, head diameter and achenes weight during autumn season. The genetic variance in UAF population for plant height, days to flowering, seed yield per plant and seed yield per acre during spring were larger than / estimated during autumn season. Phenotypic variance estimates were larger in spring season for plant height, days to flowering, seed yield per plant and seed yield per acre as compared to autumn season, while in UAF population estimates of phenotypic variance were also larger during spring than autumn season for number of leaves per plant, height, days to flowering, seed yield per acre. Estimates of broad sense heritability of all traits were significant. Estimates of high heritability were days to flowering ( .88 and .78 ) in Local open and UAF sunflower population, respectively, during spring. Likewise, low estimates of genetic variance and high environmental variance for days to maturity (Spring season) in Local open population and number of achenes per head ( Autumn season ) in UAF, resulted in low heritabilites. It was seen that marked difference occurred in the estimates of genetic covariance for most of the traits in local open and UAF population from spring to autumn season. Number of leaves per plant with days to anthesis and head diameter plant height with seed yield per plant Days to flowering with days to anthesis, with days to maturity, head diameter, and seed yield per plant and Days to maturity with seed yield per plant showed significant, positive, genetic correlation in both populations during spring season. Similarly, Number of leaves per plant with days to flowering, days to anthesis, days to maturity, head diameter and seed yield per plant Plant height with days to anthesis, days to maturity and seed yield per plant Days to flowering with days to anthesis, days to maturity, seed yield per plant, and oil content Days to anthesis with days to maturity and seed yield per plant Days to maturity with head diameter and seed yield per plant with oil content have shown significant, positive, genetic correlation in both sunflower populations during autumn season. During trait pairs viz Number of leaves per plant with days to anthesis, days to maturity and head diameter Plant height with days to flowering, days to anthesis and days to maturity Days to flowering with days to anthesis, days to maturity, and seed yield per plan Days to anthesis with days to maturity, head diameter, and seed yield per plant Days to maturity with head diameter and seed yield per plant have significant positive phenotypic correlations between each other in both local open and UAF populations during spring and autumn season. Most often, genotypic correlations were slightly higher than their corresponding phenotypic correlations in UAF ( spring and Autumn season ) But the trend was almost reverse in local open sunflower population ( spring and Autumn season ). Higher significant and positive interrelationship among undertaken traits in both populations, during the favorable environment of spring season indicates that larger number of leaves per plant, delayed anthesis and maturity but resulted into increased head diameter and more seed yield per plant. The same was the case in phenotypic coefficients among traits in both sunflower populations raised during spring season, which give rise to high oil content. The estimates for local open population ( spring season ) of percentage gains per generation for seed yield per plant and oil yield per acre indicated that family selection would be superior to autumn season. Whereas, in UAF ( spring and Autumn season ) , family selection would be superior for seed yield per plant, seed yield per acre and oil yield per acre. Selection for oil yield and seed yield per acre in local open population was expected to result in an increase in seed yield per acre and oil yield that would be 763.432 % and 914.097 % achene and oil attainable from S1 family selection for seeds and oil yield per acre, when selection for seed and oil yield per acre was carried out in UAF, favorable correlated responses for seed yield per acre ( 130.475% ) and oil yield ( 73.020 % ) , were predicted. All correlated responses, however, were appreciably more / higher than attained from direct selection for each traits. Our experiments with local open and UAF sunflower population indicated that recurrent selection in a random mating population was successful in producing diverse and potentially useful source of breeding materials. Further improvement of the populations seems feasible through appropriate recurrent selection methods and improvement in a population are expected to be paralleled by improvements in the lines selected from it. It is concluded that improvement in seed yield and oil yield can be achieved, simultaneously. Increase in seed and oil yield can be achieved by maintenance of achene number, increasing achene weight and oil concentration. Targeting yield components in this way accelerate the rate of improvement in seed and oil yield potential. The two seasons ( Spring and Autumn ) were highly diverse and hence a specific population is required for each season.
|Item Type:||Thesis (PhD)|
|Uncontrolled Keywords:||Heritability, Genetic correlations, Predicted gains, S1 Families, Sunflower, Local open, UAF, Germplasm, Estimates of mean, Coefficient of variability, Variance Covariance, Genetic, Phenotypic, Seed yield, Oil yield, Breeding program, Traits, Phenotypic, Positive interrelationship, Seed yield, Oil yield, Achene number, Achene weight, Oil concentration,|
|Subjects:||Biological & Medical Sciences (c) > Biological Sciences(c1) > Paleo-botany(c1.9)|
|Deposited By:||Mr. Abdul Qayoom Sohoo|
|Deposited On:||16 Jun 2006|
|Last Modified:||04 Oct 2007 20:59|
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