Abstract only

Characteristics of female forms used hyb- ridization and the period of pollination of emasculated flowers are considered of great importance in intraspecific crossbreeding. As a result of crossbre- eding when Georgian varieties were pol1inated by the pollen of foreign varieties, seed setting in hybrid plants was as high as 41 %, while in recervecrosses it showed 32%. Thus, tests demonstrate that the rate of seed setting in hybrids is higher at pol1ination of foreign varieties with the pollen of Georgian varieties. Analysis of vitality of hybrid grains show that in cases of high seed setting seed vitality is low and vice versa, when Georgian varieties are used as a female parent, seed setting rate in hybrids is low but is combined with the high vitality characteristics. Investigation of germination potential of hybrid grains has proved that they possess the increased germination capacity, which is rarely lower than that in parental forms. We observe the phenomenon of heterosis here. Hybrid combinations significantly differed in vitality characteristics. Vitality in hybrids frequently prevailed over the parental forms. The authentic heterosis was high when the hybrid female form was used in breeding. Authentic heterosis varied within the limits + I.I to + 11.1% in majority of the combinations. Scientific literature offers contradicting opinions on heredity of the number of days to maturity. It is noted that in the first generation earliness dominates and intermediate heredity is observed. Hybrids could demonstrate the late maturity as well. In our experiment a part of the first generation plants was earlier in comparison to the earlier parentalline ( overdominance ). Some of the produced hybrids matched early parental form. The inheritance of the trait was found to be intermediate. Thus, in our experiment the early vegetation was a dominant trait, which was strongly expressed in hybrid combinations with the early maternal form. Different opinions are observed also on the plant height. Heterosis, intermediate heredity and depression of this trait were noted. Intermediate heredity was observed in our experiment. It can be explained by the fact that Ducat variety of 88-cm height, the carrier of two genes determining short stem, participated in hybridization. Heights of hybrid plants varied within 84.4-100 cm. Hybrids were characterized by the comparatively thick and lodging resistant stem. In majority of the hybrid combinations high productive tillering dominated in the first generation. Heterosis occurred in 99% of the combinations. It varied within 1.6% to 13%, degree of heterosis being also high (hp=+ 1.1 +3.0). Heterosis of the number of grain per spike was observed in the first generation of the majority of combinations. Heterosis appeared in 75% of the direct combinations, while 25% demonstrated intermediate heredity. At the same time heterosis was expressed in 80% of the reversed combinations, while 20% of them showed intermediate heredity. Weight of grains per spike is the primary characteristic of grain yield. In our experiment 90% of the first generation combinations demonstrate overdominance and authentic heterosis in the grains weight per spike. Grain weight per spike varied from 2.8to3.2g. 1000 grains weight in parental lines of our experiment varied within 37.5-43.0 g, while in the first generation hybrids it ranged from 40,4 9 to 46,5 g, demonstrating rather high heterosis (+3.9- 7.1 %). Degree of heterosis was also high (hp= + 1.8+8.0). Thus, intraspecific hybridization allows for the production of improved germplasm with the traits valuable for breeding of winter wheat.

English

0409|AGRIS 0401|AL-Wheat Program

Juan Carlos Mendieta

CIMMYT Publications Collection