No abstract

Two mutants for sphaerococcoid seed (MA 16219) and compact spike (MA 17648) were isolated from M 3 progeny of durum wheat cultivar, Altaiskaya Niva, mutagenized with chemical mutagens. The chromosomal locations of the genes involved were determined by the use of a complete set of D-genome disomic substitutions in durum cultivar, Langdon. The gene for sphaerococcoid grain, s 16219 , was allelic to S2, located in the centromeric regionofchromosome3Binhexaploidwheat.Thegenefor compact spike, C 17648 , was located on chromosome 5AL distal to the Q locus. Using microsatellite markers, C 17648 and awn inhibitor B1 were located in the F 2 of LD222 · MA17648. The gene order was Xbarc319-C 17648 -Xgwm179-Xgwm126-Xgwm291-B1.

A common wheat (Triticum aestivum L.) mutation that produces 3 pistils (TP) per floret may result in formation of up to 3 kernels per floret. The TP trait may be important for increasing the number of grains per spike and for improving the yield potential through breeding. This trait is determined by the dominant Pis1 gene. Genetic mapping of Pis1 involved 234 microsatellite markers and bulk segregant analysis of a cross of the TP line with Novosibirskaya 67. The Pis1 gene is located on chromosome 2DL, between markers Xgwm539 and Xgwm349. This result does not agree with a previously published localization of the Pis1 gene on chromosome 5B. The possible importance of TP wheat as an alternative genetic resource is discussed.

No abstract

Triticum monococcum L. (2n = 2x = 14, A m A m genome) is one of the most ancient of the domesticated crops in the Middle East, but it is not the ancestor of the A genome of durum wheat (T. durum Desf. 2n = 4x = 28, genomes BBAA) and bread wheat (T. aestivum L., 2n = 6x = 42, genomes BBAADD). It has been suggested that some differentiation has occurred between the A m and A genomes. The chlorina mutants at the cn-A1 locus located on chromosome 7AL have been described in T. aestivum L. and T. durum, and a chlorina mutant has been found in T. monococcum. The aims of our study were to establish linkage maps for chlorina mutant genes on chromosome 7A of T. aestivum and T. durum and chromosome 7A m of T. monococcum and to discuss the differentiation that has occurred between the A and A m genomes. The chlorina mutant gene was found to be linked with Xhbg234 (8.0 cM) and Xgwm282 (4.3 cM) in F 2 plants of T. aestivum ANK-32A/T. petropavlovskyi k54716, and with Xbarc192 (19.5 cM) and Xgwm282 (12.0 cM) in F 2 plants of T. durum ANW5A-7A/T. carthlicum #521. Both the hexaploid and tetraploid wheats contained a common marker, Xgwm282. In F 2 lines of T. monococcum KT 3-21/T. sinskajae, the cn-A1 locus was bracketed by Xgwm748 (25.7 cM) and Xhbg412 (30.8 cM) on chromosome 7A m L. The distal markers, Xhbg412, Xgwm282, and Xgwm332, were tightly linked in T. aestivum and T. durum. The common marker Xhbg412 indicated that the chlorina mutant genes are located on chromosome 7AL and that they are homoeologous mutations.