Abstract

M.S. Elias, K.D. Al-Jubouri and A. Al-Daoude

In this study, morphological characterization and the Amplified Fragment Length Polymorphism technique (AFLP) were used to estimate the genetic diversity among fifteen pure inbred lines (S1, S2, --- and S15) of C. pepo. Out of the 28 primers screened, eleven EcoR1 and Mse1primer combinations were selected and amplified 622 loci of which 520 (85.3%) were polymorphic. Genetic distance values were calculated and they ranged from 0.11 to 0.56 indicating high polymorphism among studied accessions that were classified into two main clusters using the unweighted pair group’s method with arithmetic mean (UPGMA). Phenotypic studies indicated that S15 x S13 and S15 x S14 crosses were favorable as they were the most distant parents. Based on AFLP data, S1 was found to be genetically the most distant accession. Thus, S1 x S7 (PDV 0.52) and S1 x S5 (PDV 0.56) crosses were performed and their progeny was evaluated in the field mainly for productivity. S1 x S5 and S1 x S7 plants had higher yields (1.27 and 1.62Kg per plant) than their respective parents and than the commercial hybrid, Amjad (1.12kg per plant). In contrast, yields of S15 x S13 and S15 x S14 plants (0.91 and 0.89kg per plant), chosen according to morphological classification, were much lower than those resulting from AFLP crosses. AFLP data seems to be more accurate than the morphological one and should be deployed in determining parents for crosses. However the new hybrids should be tested for other important characteristics such as disease and pest resistance before they can be considered in any breeding programs.