YIELD POTENTIAL OF NOVEL RICE GENOTYPES, AND EFFECT OF Trichogramma RELEASE AND BLAST RESISTANCE ON RICE PRODUCTIVITY

Abstract

Rice is a vital food crop for about one-half of the global population. Unfortunately, it suffers from some biotic and abiotic stresses, which negatively affect the yield potential. Rice plants, in Egypt, are subject to infestation with several insect pests, but the most destructive one is the rice stem borer, Chilo agamemnon Bles. In addition, rice blast remains the most serious disease to manage. Blast resistance has consistently been one of the most important objectives of rice breeders in Egypt. The current investigation was conducted at the experimental farm of Rice Research and Training Center, Sakha Agricultural Research Station during 2014 and 2015 rice seasons. The objectives were to find out the efficiency of Trichogramma release in controlling the rice stem borer compared with insecticide, and to identify some novel resistant and high yielding varieties with high broad spectrum of blast resistance and high level of tolerance to stem borer infestation. Seventeen genotypes were evaluated under both natural and artificial inoculation for blast. Also, yield and yield attributes of these genotypes were estimated. The results revealed that all japonica genotypes were resistant or moderately resistant to the stem borer while indica and indica japonica genotypes were almost susceptible to the stem borer. The release of Trichogramma twice, each at a rate of 30,000 individuals /feddan, the first release was ten days before maximum tillering, and the second one was at 20% flowering. The release of this egg-parasitoid reduced the borer infestation, overall the 17 genotypes, by 78-80% white heads, and was relatively more efficient than the application of the recommended insecticide (Furadan at a rate of 6 kg /feddan). Consequently, Trichogramma, as eco-friendly application, could be used as an alternative management for stem borer than insecticide. Blast nursery evaluation revealed that all japonica GZ lines were highly resistant, as well as high yielding, such as GZ10364-22-3-1-2 and GZ10365-2-4-1-2. Under artificial inoculation with specific and virulent blast races, all genotypes were resistant to all aggressive races except Sakha 101 that was susceptible Till now, the genotypes,