Problems of primary seed production of some rice varieties

Abstract

Rice is a product that combines high calorie content with dietary and medicinal properties. Its consumption in our country, and throughout the world, is constantly growing. In this connection, the relevance of the need to develop new rice varieties that harmoniously combine high yield and excellent grain and milled rice quality is increasing. The key to obtaining quality rice grain and seed is competent seed production work. This article presents the results of many years of research on the possible causes of the appearance of unusual phenotypes (atypical plants) in the primary seed production nurseries of three new rice varieties, fundamentally different in architectonics - Anait (tall, early ripening and large-grain), Sharm (short, early ripening and long-grain) and Lastochka (medium-grown, medium-ripening, medium-grain). Variety Anahit was found to be of different quality according to grain thickness and the weight of 1000 grains. The range of variation in the grain thickness was 1.2– 2.4 mm, and in the weight of 1000 grains - 33.9–44.4 g. Therefore, all plants of this variety were conditionally grouped into two classes and analyzed in detail by family. In the long-grain variety Sharm, an unusual trait appeared - the spinousness of the grain. In the primary seed production nursery in 2016, out of 600 sown plots, 329 plots had different types of spinousness. It is considered that the set of chromosomes according to spinousness trait in the variety Sharm included both recessive and dominant genes (an1, An2⁕, An3⁕; An1⁕, An2⁕, an3). And in the event of an unfavorable combination of circumstances (abiotic and anthropogenic factors) in 2015, in the phase of heading-flowering in the variety during fertilization, gene unlocking occurred, as a result of which atavistic traits started being observed in the progeny. In variety Lastochka, families significantly differed both among themselves and in the years of cultivation, in resistance to blast and in the mass of 1000 grains. In the process of primary seed production during family-wide selection, families with average resistance to blast and with improved technological milled rice characteristics were identified.