Use of Natural Hybridization and Karyotypic Analysis to Study the Transfer of Base Tillering from Egyptian Clover Multi-Cut Cultivar to Mono-Cut Cultivar

This investigation was conducted at Gemmeiza Agric. Res. Station, ARC, Egypt, during the period between 2014-2016, to study the effect of natural hybridization in transferring base tillering trait from multi-cut to mono – cut cultivars of Egyptian clover. Differences between the parental types Trifolium alexandrinum Fahl, Miskawi and their hybrid was determined by  using morphological and Karyotypic analysis. The cultivar Fahl Giza 1 was used as a female parent, Miskawi Gemmeiza 1 as a male parent and the first generation  (Miskawi Gemmeiza 1 x Fahl Giza 1) were used for further cytological examination the results appeared that, the hybrid plants were multicut similar to Miskawi as will as, branching was basal similar to Miskawi and apical similar to Fahl. The blooming period in Fahl, Miskawi and hybrid was 108.00, 137.55 and 131.15 day, respectively. The differences of the blooming period among the different genotypes were highly significant. Seed number per head was 51.60 for Fahl, 44.30 for Miskawi and 68.00 for hybrid although the weight of 100 seeds in Fahl, Miskawi and hybrid was 0.31, 0.27 and 0.30 gram, respectively. Fahl and Miskawi has the same chromosome number (2n = 16) and total length of all chromosomes of each type was almost equal to the other. The length of chromosome No. 1 in Fahl was larger than of Miskawi, while chromosome No. 3 in Miskawi was larger than that of Fahl. The chromosome ratio of the long arm to the short arm in Fahl and Miskawi show difference only between the corresponding chromosomes No. 1 and 4 in both cultivars. The chiasma frequency was less in hybrid plants than in both parents. It was 12.8, 12.6 and 11.4 in Fahl, Miskawi and hypbrid, respectively. The hybrid recored the hightest percentage of cells containing chromosomal aberration (14.36%). Significant differences were obtained chromosome area, chromosome length and mitotic index among the varieties.