CHROMOSOMES ASSOCIATED WITH WAXLESSNESS, AWNEDNESS AND TIME OF MATURITY OF COMMON WHEAT

Abstract

Jensen and Driscoll (1962) reported that the waxless character of the Cornell Selection 507SaB-2B-21 of coInmon wheat (Triticzmr nestimmz L.) was controlled by a single dominant gene. T h e present paper reports on the specific chron~oson~e location of this gene as well as on the locations of genes affecting awnedness and time of maturity. From observations on the nullison~ics of Chinese Spring, M. I\/luramatsu3 concluded that chron~oson~es 2A, 4B and 6B bear genes for wax production. On observing that Chinese Spring monosonlic 4B was also waxless, he concluded that in this bacltground the gene on this chrornosoille is henlizygously ineffective. Allan and Vogel (1960), by aneuploid F, observations, located a dominant gene for heavy wax production on chron~osome 2A of a durum selection. By monoson~ic analysis, Tsunewalti (1962) located a single dominant gene for inhibition of wax production on chromosome 2D of a synthesized hexaploid wheat. From F, monosomic analysis Tsunelvalti ( 1961) concluded that Chinese Spring bears a gene on chron~oson~e 2A for waxy foliage and that the non-waxy hexaploid strain Salnlon is deficient for this locus. It was also concluded that chronlosome 5D appears to carry a gene for waxiness. Froill the results of a number of investigators it is ltnonrn that Chinese Spring possesses two major inhibitors of awn development, H d and B,; it is consequently classified as hooded beardless. Sears (1941) located H d and B2 on c~lromosomks 4B and 6B respectively. Selection 5075aB-2B-21, being bearded, possesses no inhibitors of awnedness; therefore, it differs from Chinese Spring by two major genes for this character. \Vatlcins and Ellerton (1940) observed that the F2 between these t\vo genotypes contained the parental types and the two recombinants, tipped 2 (hd B,) and hooded bearded ( H d b.). One of these inhibitors, B2 was repor!ed to affect glunle bealt shape by Siklca et nl. (1959), in that b2 b2 \\-as associated with an acuminate condition and B2 associated with an acute glunle bealt. A number of illinor genes affecting anrnedness have subsequently been located by various authors. Heyne and L~vers (1953) located awn promoting genes in the variety Pawlnee on chromoson~es 3A, 3D and 7D. Fro111 observations on different crosses various inheritance Datterns of time of niaturity have been reported, such as multiple factors ( ~ a i n & and Singleton, 1926), three major genes as well as illodifiers (Powers, 1931), at least two factors (Nandpurj, 1958) and one factor (El-Khishen, 1953). By observations on nullisomics, Sears (1 911, 1951) located genes for earliness on chromosomes 2A, 2B, 3D, 4B, SA, jB, j D and 6B of Chinese Spring, that on chron~oso~nes 5D being the most important. By monosomic analysis filorrison (1960) con-