Immunological variability of rice varieties depending on growing conditions

Federal Scientific Rice Centre, Krasnodar, Belozerny, 3350921, Russia

^* Corresponding author: olesya.bragina.1984@mail.ru

Abstract

Blast (causative agent Pyriculariaoryzae Cavara) plays an important role among economically important, dangerous and harmful rice diseases of rice in all rice-growing countries, including Russia. The problem of resistance of rice plants to disease is one of the main problems in modern breeding in most countries. Intensification of rice cultivation creates a favorable microclimate in the sowing agrocenosis for the development of blast disease and leads to an increase in its harmfulness. The varieties quickly lose their resistance to new races of the pathogen, due to high spontaneous variability of the M. grisea fungus, its field populations are usually represented by a mixture of races with different virulence and aggressiveness, outstripping the evolution of the host plant. The nature of the blast manifestation depends on the agroclimatic conditions and genotype. The article presents the results of research at experimental and production plots of Federal Scientific Rice Centre (FSC of Rice) and Elite Seed-Production Experimental Statation Krasnaya (ESPES Krasnaya). It has been shown that a clear differentiation of rice varieties in terms of blast resistance and yielding properties is possible only when certain (provocative) conditions are created that contribute to the manifestation of their genetic potential, while the blast resistance of varieties cannot be provided only by the introduction of one gene of racespecific resistance. A close negative relationship was obtained between the yield and the intensity of blast disease on two backgrounds of mineral nutrition: N-1 - r = -0.93; N-2 - r = -0.95. The determination coefficients showed that in 86.8 - 90.1% of cases, the yield is due to the intensity ofblast development on the crops of the studied rice varieties.