Morphological, Germination, Bolting and Cytogenetical Characteristics of Fourteen Promising Garlic Genotypes

Abstract

Some growth and cytological features were studied on fourteen garlic (Allium sativum L.) genotypes in the growing seasons of 2005 - 2006. These materials were four cultivars (Egaseed 1; Sids 40; Egaseed 2; Egyptian) and ten clonal selections (AZO 1; AZO 2; AZO 3; AZO 4; AZO; EGA 1; EGA 2; EGA 3; EGA 4; EGA 5). Most cultivars and clones showed a quit good germinations after 15 and 30 days from planting. However, the clone EGA 3 and cultivar Egaseed 2 had a low germination percentages (31.4 and 48.6%, respectively, i.e. the lowest) after 15 days from planting while the cultivar Sids 40 scored the lowest value (85.0%) after 30 days from planting. On the other hand, the flower- stalk which appeared in either sponge (soft-neck) or solid (hard-neck) forms are only found in cultivar Egaseed 2 and clones EGA 3 and EGA 4 and their percentages were significantly different. These genotypes could be considered as complete bolting type. Chromosomal studies showed that all investigated materials have a diploid number of 16 (2n = 16). Although lot of good metaphase spreads were examined and scored, the numbering and adjustment of the homologous chromosome pairs were very difficult due to; (1), the existence of high percentages of large fragments that misleads the karyotype making; (2), it is not easy to determine the centromere position because of the presence of one or more chromosomal constrictions or chromosomal breaks which are very similar to the centromer in their appearance; (3), there are great variation in satellite number and size among the studied genotypes. Statistical analysis showed that the highest value of mitotic index (MI) was obtained from the plants of cultivar Sids 40 (10.03 ± 2.1) while those of clone AZO 4 exhibited the lowest one (3.42 ± 2.1). Data also revealed that there were considerable variations among the studied genotypes at the level of the mean percentages of prophase, metaphase and ana-telophase. The mitotic aberrations were only examined at metaphase and ana-telophase cells. The recorded abnormalities included chromosomal and chromatid bridges, chromatin stickiness, chromosomal breaks and fragments and polyploidy. Data showed that cultivar Sids 40 and clone EGA 5 had the highest values of total chromosomal abnormalities while clones AZO 4 and AZO 1 had the lowest values.