The understanding of the generated hybrids' breeding value gives a measure of probable advances in a breeding program. Four cocoa genotypes (testers) were crossed with two distinct lines (T65/7 and T86/2). The parents and the hybrids were separately established in randomized complete block design with six replications. The fourteen genotypes were evaluated for pod length (PL), weight (PW), beans/pod (NoB), bean length (BL), width (Bwi) and thickness (BT). The treatment, parent, crosses and Line x Tester sources of variation were significant (P ≤ 0.05). Hybrids from the same maternal parent differed significantly (P < 0.05) for the six traits. Contribution to the total variance of PL, PW and Bwi were in the following order: Tester > Line x Tester > Lines. The highest general combining ability (0.42) occurred in T65/7 for PW; the least (-0.081) occurred in T86/2 for PL. Cross combination T65/7xT57/22 produced the highest specific ability of combination (4.33) for NoB. Variance of GCA and SCA were significant (P < 0.05) for the six traits. The GCA/SCA ratios revealed the inheritance of PL, PW, Bwi and BT to be additive. Non-additive gene effect controlled NoB and BL. Heterosis for the six traits ranged between -17.82% for BT (T65/7xT57/22) to 52.40% for PW (T65/7xT53/8). Increased productivity in cocoa is possible through hybrid breeding programs.
The understanding of the generated hybrids’ breeding value gives a measure of probable advances in a breeding program. Four cocoa genotypes (testers) were crossed with two distinct lines (T65/7 and T86/2). The parents and the hybrids were separately established in randomized complete block design with six replications. The fourteen genotypes were evaluated for pod length (PL), weight (PW), beans/pod (NoB), bean length (BL), width (Bwi) and thickness (BT). The treatment, parent, crosses and Line x Tester sources of variation were significant (P ≤ 0.05). Hybrids from the same maternal parent differed significantly (P < 0.05) for the six traits. Contribution to the total variance of PL, PW and Bwi were in the following order: Tester > Line x Tester > Lines. The highest general combining ability (0.42) occurred in T65/7 for PW; the least (-0.081) occurred in T86/2 for PL. Cross combination T65/7xT57/22 produced the highest specific ability of combination (4.33) for NoB. Variance of GCA and SCA were significant (P < 0.05) for the six traits. The GCA/SCA ratios revealed the inheritance of PL, PW, Bwi and BT to be additive. Non-additive gene effect controlled NoB and BL. Heterosis for the six traits ranged between -17.82% for BT (T65/7xT57/22) to 52.40% for PW (T65/7xT53/8). Increased productivity in cocoa is possible through hybrid breeding programs.
Background: Indian spinach is one of the important underexploited tropical leafy vegetables which have high nutritional and medicinal value. Molecular marker technology has greatly accelerated the process involved in breeding programs for the improvement of various crops and its techniques have been considered to be the most suitable means of estimating genetic diversity.
Aim: The study is to determine the genetic diversity among the accessions of Indian spinach collected from South western Nigeria using molecular markers.
Methodology: Random amplified polymorphic DNA (RAPD) markers were used to assay 20 accessions of Indian spinach (Basella spp) collected from the south western states of Nigeria (Oyo, Osun, Ogun, Ondo and Ekiti).
Results: Results showed that RAPD markers were highly polymorphic and generated alleles ranging from two to eight. The polymorphic information content was highest for the OPT-17 primer (0.757) and the mean average was (4.23) Moreover, gene diversity (0.785) was high, and cluster analysis delineated the accessions into five groups, which indicated that a significant genetic diversity was present among the accessions studied. A dendrogram clustering method revealed five major clusters. Clusters I, II and IV had one accessions each, III had four and V had thirteen accessions.
Conclusion: The result revealed that RAPD markers are useful for genetic characterization as they provide information on the interspecific and phylogenetic statuses of the accessions. The markers also showed a genetic variability that could be exploited for varietal delineation and improvement of the vegetable in Nigeria.
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