Estimation of Heterosis and Combining Ability in Some Genotypes in Okra
Abstract
This study was conducted in the experimental field of the Agricultural Protected Environment Center – Sana’a University, during two seasons (2016) (2017), where in the first season (36) okra genotypes were collected from different agricultural regions in Yemen, and they were evaluated, classified and coded from The research team of the Genetic Origins Center in the General Authority for Agricultural Research and Extension – Dhamar accepted, and they were as follows: 17 models from Hadhramaut, 11 models from Hodeidah, two models from Hajjah, 3 models from Marib, and one model from each of Al-Jawf, Taiz and Al-Mahra, and based on their field performance, ( 10) genotypes are
Hadhramout (Syaoon) * Wady Bn Ali (Syaoon) * Wasid al-guba (Tarim)
Sahil AL mqramh (Shabam) * AL-hudaydah (Zabid) * AL-hudaydah (Bagil)
Reba,al-mahal-shryg,mahfwd (Hais) * AL-equl Gabal Assahl (Marib)
Hajah (Harad) * Al-gawf) AL-qadimah AL-kharab and inserted into an interbreeding program according to the second Griffing method, which includes the possible combinations between the parents in one direction with the participation of the parents and without the reverse crosses, and the number of genotypes was 55 genotypes according to an equation (P+1)/2
It was randomly distributed to the experimental units and with three replications by designing randomized complete blocks (RCBD), and the study aims to evaluate the performance of some individual hybrids resulting from the semi-cross-crossing between a number of local okra cultivars and compare them with their parents to find out the best parents and hybrids produced in terms of high production, desirable traits and continuity. The superior ones for inclusion in future breeding and improvement programs for this crop and the estimation of some genetic parameters such as heterosis, general and specific combination ability, degree of heritability, degree of dominance and correlation between traits. The data related to the traits were recorded, plant height (cm) – number of branches / plant – stem diameter / cm – number of leaves / plant – average number of leaves – leaf area – early flowering – average number of total flowers / plant – set percentage – yield amount Early yield g / plant – average number of fruits / plant – average fruit weight
Plant yield (g) – fruit length (cm) – fruit diameter (cm) – number of seeds in the fruit – percentage of fiber in fruits.
The results of the parents’ assessment confirmed the existence of highly statistically significant differences between the parental genotypes of all the studied traits. The AL-hudaydah (Bagil) genotype occupied the first position for all flowering traits (early flowering / day * average number of total flowers / plant * average contract percentage %)’ While AL-hudaydah (Zabid) * AL-hudaydah (Bagil) * Reba, al-mahal-shryg, mahfwd (Hais) outperformed in the characteristics of the yield and its components (early yield (g / plant) average plant yield / g) and also was They excel in the most important characteristic for evaluating the phenotypic characteristics of fruits, which is (the number of fruits / plant) and in the characteristic (the percentage of fiber in the fruits).
The study of crosses showed the presence of a highly statistically significant hybrid power in all the studied traits and calculated on the basis of the deviation of the average of the first generation from the best of his parents. While other crosses showed hybrid strength for some traits, both parents showed high phenotypic values for these traits or differed in these values with the presence of geographical and genetic distance between them.
The variance of both the general and private abilities of the coalition was highly statistically significant in most of the studied traits, and this indicates that the inheritance of these traits is caused by the actual genes with a cumulative and non-cumulative effect at the same time. It has been shown that the ratio of the variance of the ability of the general to the specific coalition was less than the correct one in nine of the studied traits, which indicates that these traits are the result of the control of genes with a non-cumulative effect more than they are caused by genes with a cumulative effect, and more than the correct one in the rest of the traits. This indicates that the cumulative effect of genes was the largest.
The results indicated that the values of the degree of dominance for most of the traits are less than the correct one except for the characteristics of leaf area – early flowering – early yield (gm / plant) – fruit weight / g fruit length / cm – fibers in fruits, which were greater than the correct one in any direction The presence of the effects of the super-dominant genes.
The analysis of the simple apparent correlation between all the studied traits showed the presence of some positive, significant, and statistically significant correlations between these traits, as well as some significant negative correlations with statistical significance.
The results indicate that some cultivars can be used in the breeding program to derive highly efficient hybrids at the level of productivity, their components and qualitative traits. It was also shown that the subordination of traits to the cumulative effect of genes makes the selection program a successful method for devising new stable varieties of okra.