The effects of wheat chromosome 1D on kernel protein and various flour characters have been investigated in several studies. The monosomic state of 1D gave higher kernel protein values than the disomic state in 'Kharkof MC22' (WELSH and WATSON 1965) and in Chinese Spring (JHA et al. 1971). JHA et al. also found that, in crosses between Chinese Spring 1D monosomics and 'Sonora-64' or 'Lerma Rojo', the F₁ monosomics and their F₂ and F₃ progenies all gave higher protein values than disomic counterparts. Yields and kernel weights were not reported in either of those studies, so it is not known whether increased protein values were associated with reduced yields or with lighter seeds. JOPPA et al. (1975) added a pair of Chinese Spring 1D chromosomes to the tetraploid durum cultivar 'Langdon'. The semolina protein content was 2 to 3% higher in the 1D disomic addition line than in durum cultivars, including Langdon, but the grain yield was lower. The authors thought that the increased protein content might be associated with decreased yield.

Each of the Cheyenne 1D substitution sublines in the present study had lower kernel and flour-protein values than either parent. Yields of the sublines, except for Subline 80, were between those of the parental cultivars, and 1000-kernel weights were equal to or lower than that of Chinese Spring, which had lighter kernels than Cheyenne. The "1D" line had a higher protein value than either parent, but its yield and kernel weight were markedly reduced by high temperatures.

Several studies have been made to determine the effect of chromosome 1D from different sources on flour characters. WELSH and HEHN (1964) considered 1D to be "extremely important in the determination of bread flour characteristics". They found that the monosomic state of 1D resulted in a deterioration of mixing quality and gas-retention capacity both in the weak-quality parent, Kharkof MC22, and in F₂ progenies of F₁ monosomic plants with 1D derived from the strong-quality parent,' 'Itana'. They concluded that genes carried by 1D could not function effectively in 3n-2 endosperm, which would occur in about 75% of the seeds produced by monosomic plants.

WELSH et al. (1968) tested 'Hope' 1D and 'Timstein' 1D substitutions in Chinese Spring for five flour quality characters. None of the characters in the Hope 1D line were significantly different from those in Chinese Spring. The Timstein 1D line had significant negative deviations for loaf volume and valorimeter (a measure of dough strength). On the other hand, our tests of the Cheyenne 1D substitution in Chinese Spring indicated a positive effect of 1D on dough characters. Thus, different sources of 1D can give a range of effects in the genetic bakcground of Chinese Spring.

The addition of two doses of chromosome 1D to durum wheat produced dough with strong mixing properties which were lacking in a sister line without 1D and in the durum cultivars (JOPPA et al. 1975).

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