Genetic analysis of photosynthesis and productivity in corn

Abstract

The genetic relationships among different inbred stocks of corn with respect to different indices of photosynthetic efficiency and plant productivity was assessed by means of diallel graphs. The salient feature of the current study was "apparent overdominance" for some important indices of photosynthetic efficiency, viz. photosynthetic rate/unit leaf area (at the silking stage), total chlorophyll content and chlorophyll a content, as well as for total dry matter production and economic yield. The results could be explained in terms of complementary gene action and the multiplicative effects of the sub-components that comprise these traits. However, complete dominance was recorded for photosynthetic rate (at the grain filling period), leaf area/plant, number of leaves/plant, number of leaves above the ear, ratio of chlorophyll a/b and harvest index. In the majority of cases graphic analysis was possible only when a number of epistatic parents were omitted from the analysis. Although the position of the array points for different indices of photosynthetic efficiency was consistent across the years, the ontogenetic and seasonal differences in the genetic behaviour of parents, meaning thereby, different loci being active at different stages and seasons, was apparent. The same was true for the epistatic parents. Non-allelic interaction of the genes rather than the non-random distribution of the genes among the parents seemed to be the most common cause of disturbance in the Wr/Vr relationship.Inbred stock MG 115 was identified to be the most promising because it embodied an efficient photosynthetic machinery by virtue of increasing the number of alleles for a majority of the indices of photosynthetic efficiency, thereby enabling it to register the highest biological productivity and economic yield. Further, inbred stocks MG 138, MG 121, and MG 125 were also promising for different photosynthetic parameters.

The influence of low-temperature on the photochemical activity of chloroplasts and activity of antioxidant enzymes in maize leaves

“…We also found that the positive dominance is the most important genetic effect determining heterosis in photosynthetic characteristics in the F1 generation, which agrees well with results of other studies made on nonstressed maize plants (Mifflin and Hageman 1966, Crosbie et al 1978, Baer and Schrader 1985, Mehta et al 1992. The increase of heterosis, observed during low temperature stress for some parameters, could be explained by the change of dominance level or the restriction of negative dominance.…”

The evaluation of photosynthetic parameters in maize inbred lines subjected to water deficiency: Can these parameters be used for the prediction of performance of hybrid progeny?

“…And herein lies the main problem: although the quantitative genetic analysis of our data showed that the additivity certainly can play an important role in the inheritance of the photosynthetic pigments content, the nonadditive (particularly dominance) genetic effects were even more important. Similar phenomenon was found by Oelke and Andrew (1966), Baer and Schrader (1985) or Mehta et al (1992), who also analyzed various components of genetic variation in the Chl content in maize leaves. As regards P N and other leaf gas-exchange parameters, we have found not only the presence of the dominance genetic effects, but the maternal effects as well, so the situation here is even more complex.…”

“…Genotypic differences in the content of Chls in maize leaves were found e.g. by Oelke and Andrew (1966), Rao et al (1978), Monma and Tsunoda (1979), Baer and Schrader (1985), Crafts-Brandner and Poneleit (1992), Mehta et al (1992) or Krebs et al (1996), and the intraspecific variability in Chl fluorescence parameters was also described for this plant species in some previous papers (e.g. Csapó et al 1991, Dolstra et al 1994, Krebs et al 1996.…”

The effects of brassinosteroids on photosynthetic parameters in leaves of two field-grown maize inbred lines and their F1 hybrid

“…1), confirming again the previous findings that F1 hybrids of maize show positive heterosis not only for yield and morphology parameters, but for various photosynthetic parameters as well (e.g. Baer and Schrader 1985, Mehta et al 1992, Holá et al 1999, Ahmadzadeh et al 2004, Kočová et al 2009). The inbred line CE704 was characterized by the lowest content of Chls and Cars and usually also by the lowest PS 1 activity and HRA (Fig.…”