Influence of gametocidal chromosome 4S' on the segregation ratio in genetic analysis of the common wheat lines.

摘要

The character "hairy leaf sheath" was studied in two groups of introgressive common wheat lines and shown to be under control of dominant gene Hs being situated in chromosomes 4S; 4D of Aegilops sharonensis and Triticum miguschovae (AAGGDD), respectively. Using experimental data on genetic analysis of introgressive Unes for character "hairy leaf sheath" controlled by the gene of "cuckoo" chromosome 4S; the algorithm for calculation the theoretical segregation ratio in F2 was developed. Segregation distortion is caused by non-viability of majority of gametes lacking 4S'. Frequency of functioning gametes without 4S' is determined by the probability p. Then, the ratio 7 nonviable : 9 viable zygotes is formed as O.lp-.5 Ifi: 0.25+0.5p+0.25p Since segregation involves two characters, gamete viability and hairiness, not monogenic ratio 3:1 but ratio 15 hairy : 1 hairless was used as a base for search of frequency p by maximum-Ukelihood method. Using 16 populations F2 from crossing lines differing in character studied, it was shown that theoretically expected ratio is equal to 0.9676:0.0325 and 0.9787:0.0213 in two different years. Judging y the criterion, actual segregation ratios do not differ from theoretical ones calculated using p, the frequency of fiinctioning gametes lacking the "cuckoo" chromosome.