| Inheritance of leaf area in vulgare wheat M. KRALJEVIC-BALALIC Department of Genetics and Plant Breeding, University of Novi Sad, Novi Sad, Yugoslavia In recent years, the role of the green parts of plants in determining the yield of different genotypes has been intensively studied. In order to recognize more completely the components of grain yield, studies on the role of different leaves, internodes, spikes, and awns have been conducted (WATSON et al., 1963; DAVIDSON, 1965; KUMAKOV, 1968; SIMPSON, 1968). No strong correlation between the leaf area and yield was found (WATSON, 1952; ASANA, 1955; STOY, 1965; BOROJEVIC and CUPINA, 1969). A particular significance in organic matter formation is attributed to the flag leaf and the green area above it. The intention of this paper is to examine certain characteristics of the leaves which could be found useful in the selection for high yield. The objective of the research reported was to examine the mode of inheritance of leaf area, its heritability and combining ability. Material and Method In diallel crossings of four wheat varieties (short-straw Mara and Bezostaia-1, semidwarf Sava, and dwarf NS-732), the mode of inheritance, heritability, and combining ability of the leaf area were studied in the F1 and F2 generations. The size of the leaf-lamina area per plant in cm2 was determined by the weight method (ALEKSEENKO, 1959). The analyses of variance of the data on the combining ability and the estimation of various effects were made by the Griffing technique, method 4 (1956). The heritability estimation was made according to MATHER (1949). Results and Discussion The Mara variety had the largest leaf area, then Sava and Bezostaia-1, while NS-732 had the smallest (Table 1). In the F1 generation the combinations Bezostaia-1 x Mara and Mara x NS-732 had the largest leaf area. The hybrid Bezostaia-1 x Sava had the smallest (Table 1). The total leaf area in wheat showed a continuous variability, which is typical for the majority of quantitative characters. In the F1 hybrids examined the leaf area was largely intermediate in Mara x NS-732 and Sava x Mara and incompletely dominant in Bezostaia-1 x Mara (Table 1). This can be explained by the presence of a number of genes which had additive effects. The F1 combinations NS-732 x Sava, Bezostaia-1 x Sava, and NS-732 x Bezostaia-1 showed full dominance (Table 1). The differences between the parents of these hybrids were not significant. In all the F2 combinations segregation occurred, the mean value was lower than in the F1 generation, and the total leaf area was intermediate in relation to the parents (Table 1). The flag leaf comprised 44% to 50% of the entire leaf area. In their inheritance, the flag leaf and other leaves behave similarly to the total leaf area. The genotypic variability was high in the morphological and physiological characteristics, which confirmed the results of research on barley conducted by YAP and HARVEY (1972). The heritability of the entire leaf area in barley ranged between 24% and 73% (FOWLER and RASMUSSON, 1969). In our tests the heritability ranged between 6% and 47%. The negative value of heritability in Bezostaia-1 x Sava indicated that probably no genetic difference in relation to the examined characters exists. Combining Ability The variance of GCA (general combining ability) was highly significant for the total leaf area, while the variance of SCA (specific combining ability) was not significant (Table 2). SINGH and GUPTA (1969) arrived at the same conclusion. BROWN et al. (1966) maintain that the SCA in wheat is absent. The best combiner for the total leaf area was Mara, then Bezostaia-1 and NS-732, and the worst was Sava (Table 3). The SCA was significant only in the combinations NS-732 x Sava and Bezostaia-1 x Mara (Table 3). A separation into the SCA and GCA indicated that the additive genetic variance comprised the main part of the total variance of the six examined F1 hybrids. This concurs with the results of HSU and WALTON (1970) and BHATT (1971). |
| Copied from the Proceedings of the 4th Wheat Genetics Symposium by the kind permission of the Editors and Organizing Committee. |