Development of Autotetraploid Perennial Rye (Secale montanum Guss.) and Selection for Seed Set

Abstract

Different concentrations of colchicine solution (0. 1% and 0.2%) and temperatures (24 and 27 o C) were applied to wild diploid rye and autotetraploid forms were produced. Five hundred seedlings were placed into Petri dis hes for each treatment (total 2000). Cytological research was ca rried out on root tips of plants in C 0 and C 1 generations. Live seedling rate and tetraploid plant rate were change d by 6.4 ‐ 37.4 % and 8.75 ‐ 37.04%, respectively based on treatments. Plants forming the C1 generation were determined as 68.12% tetraploid, 14.71% diploid, 16.89% aneuploid (13.35% hypoploid, 3.57% hyperploid) and 0.27% triploid. Chromosome numbers of aneuploid plants ranged between 2n=19 - 29 and it was determined that plants having a chromosome number of 2n=27 were the most common. Other aneuploid plants (2n=19 - 26) were rare. Prior to chromosome counting in the C 1 generation, the seed lots were divided into five seed size groups (9-11 g, 11-13 g, 13-19 g, 15-17g, 17-19 g). Chromosome numbers were determined by a modification of the conventional root tip squash technique. Chromosome numbers varied with seed size. The rate of tetraploids, diploids and aneuploi ds were varied between 17.86-87.25%, 2.04-42.86%, 10.71- 39.29 %, respectively. As the size of seed was increased, th e rate of diploid and aneuploids decreased. Seed se t rate, spike length and the number of spikelets in plants belonging to different generations (C1, C 2, C 3 and C 4) were investigated. Seed set rate was increased from 30.51% to 61.45% with the selection of plants passing over general average in respect to seed set in each generation, however, it was determined that spike length and number of spikelets decreased. The differences were generally highly significant.