Change of quantitative traits of androgenic maize plants --Zavalishina, AN, Tyrnov, VS, Nekrasov, AM It has been shown that androgenic haploids, obtained by the method of androgenesis in vivo after pollination by a nucleus donor and then diploidized, reveal changes in the pigmentation of plants. The nucleus donor has brown colour pigment controlled by genes a1 B1 Pl1 R1. While displacing the genome of the nucleus donor in other cytoplasms there appear plants of light brown, tan and green colours. This testifies to expression changes of nuclear genes B1, Pl1 (MNL 69:120-121, 1995; MNL 72: 74-75, 1998). These changes have a strongly pronounced phenotypical manifestation, and their inheritance is subject to certain regularities analogous to paramutation of B1 and Pl1 genes. Further investigation of the diploid generation of androgenic haploids has shown that besides pigmentation other quantitative traits can be changed. The results of the changes of such traits as plant height and length of first ear are presented in this article.

Generations of androgenic plants having a nucleus from a BMS line with nuclear genes a1 B1 Pl1 R1 and cytoplasms of two different stocks: N-type from line HPL1 - N(HPL1) and T-type from line AT - T(AT) were used in the experiment. From BMS in cytoplasm T(AT), besides the generation of brown coloured plants, the generations of light brown and two green plants were used. The generations of two plants were used from BMS in cytoplasm N (HPL1). All the generations were obtained after pollination by a nucleus donor. The nucleus donor BMS-line was used as control. This line was aligned according to the quantitative traits and plant colour. We have been observing this line for 20 years.

In Figure 1 confidence intervals of plant height, and in Figure 2 confidence intervals of length of the first ear are presented. Both BMS plant generations in cytoplasm N (HPL1) differ greatly by 20-25% according to the height of the plant of the nucleus donor. In the BMS generation in cytoplasm T(AT) we can observe variations in plant height. The generation of light brown plants exceeds by 10% in height the generation of both green plants, which seem to be 5% shorter than plants of the nucleus donor. If we take the length of the ear, the picture is different. BMS in cytoplasm T(AT) differs slightly from the nucleus donor, but BMS in cytoplasm T(AT) in all variants exceeds by 20-50% the nucleus donor. In particular, in the generation of light brown colour plants the ears are 1.5 times greater than the ears of the donor. From this it follows that traits can be altered: they can be reduced and enhanced by the choice of the proper source of cytoplasm.

The results testify to the important role of cytoplasm in the change of most important quantitative traits. They can be useful for revealing the reasons and mechanisms of genome instability, trait variability, and loss of sort quality. Productivity improvement due to cytoplasm is of great interest. For it is necessary to reveal and study new sources of cytoplasm which can lead to trait change in the necessary direction.

Figure 1. Plant height confidence intervals.

Figure 2. Ear length confidence intervals.

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