The use of Heterosis and Selection Index for Improving some Important Characteristics of Sweet Melon (Cucumis melo L.)

Abstract

A breeding program was carried out at Sabahya horticultural research station, Alexandria, Egypt, during the period fringe in the autumn season 2011 till the late summer season 2013. The first part of the study aimed to measure the magnitude of development after two cycles of selfing with selection using selection index method, for two locally lines produced (lin1 Orange flesh and line 2Sandafa), selfing with selection technique was done in the autumn season of 2011 and the summer season of 2012, and the evaluation of the two selection generations was carried out in early and late summer seasons of 2013. The second part of the study aimed to produce all possible crosses (a complete diallel) between five locally produced lines (with a high degree of homogeneity to be considered approximately pure lines). Crossing among the five lines (Line 1 Kuz-El-Asal, Line 2Charantais, Line 3green flesh, Line 4Matruh and Line 5primal) was done in the autumn season of 2011, and the hybrids were evaluated in the summer seasons of 2012 and 2013. Selection index of five important characters had a big role in increased the mean values for these traits.Range values declared that the homogeneity became more within individual for most of traits in second selection generation and check variety compared with original population. Most important significant positive correlation relationships were detected among average fruit number / plant and total yield / plant, net weight with each of the flesh thickness, placenta hardness and netting, flesh thickness with each of the placenta hardness and netting, placenta hardness and netting. In conclusion it could be reported that the hybrids and check variety (Ananas Monanasa) scored the highest values in most characters under studies. Heterosis values were significant and positive over mid-parent and better parents in most crosses for all characters under studies, and most of dominance degrees had appeared.