II. 34. Several more cases of maternal inheritance of chlorophyll mutations in barley.
T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523, U.S.A. (1)
(1) Supported in part by the NSF Research Grant (GB30493) and Colorado State University Experiment Station Hatch Project.
In his previous paper (Tsuchiya, 1975a) the present author reported all 15 cases of maternal inheritance of chlorophyll mutations so far reported in barley; 11 cases of chlorina and 4 cases of streaked mutations. Several more cases of maternal chlorophyll mutations are reported in this paper. Additional information on several stocks will also be presented.
A total of 11 chlorophyll mutations showed maternal inheritance in this experiment. The name of the stocks, characteristics, and other identification are presented in Table 1. Two stocks (B15-11 and T12-26) were already proved to show maternal inheritance (Tsuchiya, 1975a, b). Detailed character expressions will be reported in a separate paper.
Table 1. List of the genetic stock used in the experiment.
As presented in Tables 1 and 2, T12-23 had two types, yellow streak and pure chlorina. T12-24 also had two types, but only pure chlorina was used in this experiment. T12-26 segregated two types, white streak and chlorina.
Table 2. Phenotype of F1 hybrids between various chlorophyll mutations and green plants.
Table 2. Phenotype of F1 hybrids between various chlorophyll mutations and green plants, continued.
Reciprocal crosses between these mutants and green parents were made in nearly all possible combinations. The results of Fl analysis were presented in Table 2.
F1 hybrids between five pure chlorina stocks (B15-11, T2-7, T5-4, T12-24, T14-6)1crossed with green plants (as the male) were all chlorina similar to the female parents, while the F1 plants from the reciprocal crosses were all green. The results suggest that these five stocks are maternal type mutations. The pure chlorina segregant in T12-23 (T12-23b) also showed maternal inheritance.
F1 hybrids from crosses between two yellow streaked mutant stocks (T12-23a and B12-6) and green male plants showed yellow streaked traits, while the F1 plants from the reciprocal crosses were all green. This again suggests that these yellow streaked mutants were maternally inherited mutants.
T12-26 was already proved to have maternal nature of inheritance (Tsuchiya, 1975a, b, 1976). Since the stock segregated white streak and almost pure chlorina in 1976, crosses were made between mutants and green plants. F1 hybrids between white streaked plants and green male segregated albino (lethal) and white streaked plants. F1 plants between pure chlorina and green male were all yellow streaked.
Three other stocks behaved differently from the stocks mentioned above. F1 plants from the cross of B15-10 (white streak) and green male segregated three white streak and seven green plants. Since only three plants showed maternal trait, it is not clear whether or not B15-10 is a maternal mutant, even though the maternal inheritance of the white streak is suggested. More data are needed to reach a final conclusion.
One albino was found in 12 F1 plants from the cross between white streaked plant of T2-16 and green male. More information is necessary to determine whether or not T2-16 is maternally inherited white streak.
The breeding behavior of T14-10 is similar to that of T2-16 and the maternal nature of this chlorina mutant is still questionable.
Based on the results so far obtained from the experiments with maternal chlorophyl mutations, the following two things have been shown:
(1) Different penetrance of the streaked characters.
As already reported in a previous paper (Tsuchiya, 1976), three-streaked mutants showed varied penetrance of the diagnostic trait. Ahokas (1976) also reported similar cases in barley. As will be reported elsewhere, all streaked mutants used in this experiment also showed segregation of different degrees of streaked traits.
It is particularly interesting to note that pure chlorina plants segregated in the progenies of yellow streaked plants in three stocks; T1-27, T12-23, and T12-24. The origin of maternal pure chlorina reported in this and previous papers (Tsuchiya, 1975a) could have resulted from this kind of segregation.
(2) Sources of different maternal stocks in the Stock Center of Colorado
The character expression of various maternal chlorophyll mutants were similar to each other. This finding led the author to study the sources of each mutant stock. The survey of the stocks showed that T1-27, T2-19, T5-7, T12-23, T12-24, and T13-23 were all most likely derived from the same stock 54-4080 of the variety Trebi. T1-27, T12-23, T12-24 were proved to be maternal inheritance. T5-7 and T13-23 are now under investigation.
Several pure chlorina stocks were, as mentioned above, derived from yellow streaked mutants and given new separate stock numbers (Table 1).
References:
Ahokas, H. 1976. Two segregating cytoplamic mutants pf barley. Hereditas 82:187-192.
Tsuchiya, T. 1975a. Five more cases of maternal chlorina in barley. BGN 5: 60-62.
Tsuchiya, T. 1975b. Further information on the inheritance of some striped (streaked) mutations in barley. BGN 5:63-64.
Tsuchiya, T. 1976. Varied penetration in the maternal streaked mutants in barley. BGN 6:78-79.
