JWSS - Journal of Water and Soil Science

  Blast, caused by Magnaprthe grisea, is often an important fungal disease in the production of rice in temperate and tropical areas including Iran. To determine reaction of rice cultivars against blast disease, 40 rice genotypes from Iran and other sources from Asia were selected. Four blast isolates from different races were used to test all rice genotypes in different greenhouse tests. In blast nursery, experiments were conducted in a Randomized Complete Block Design (RCBD) with three replications. In different experiments inoculated plant materials were evaluated for Infected Neck Number(INN), Neck Lesion Size(NLS), Infection Type(IT), Diseased Leaf Area(DLA), Area Under the Disease Progress Curve(AUDPC), Lesion Number(LN), and Sporulating Region Diameter(SRD). Most of the Iranian traditional cultivars together with CO-39 and C104-PKT showed susceptible reaction for AUDPC, IT, INN and NLS. Performance of improved cultivars from Iran, IRRI and NILs (except C104-PKT) was resistant. Some cultivars including Fujiminori, Onda , Hassan saraii were moderatly susceptible to leaf blast in blast nursery. All components of resistance in both growing stages in greenhouse and nursery tests were significantly correlated. In some cases such as cultivar Haraz different reaction was observed in seedling and flowering stages, indicating that genetics of resistance in two stages could be different.

In order to investigate the effects of furrow irrigation and amount of irrigation water on yield and water use efficiency of corn, an experiment was conducted as a split plot based on a randomized complete block design with three replications for a period of two years at Agriculture Center of Mazandaran. Treatments included three levels of 100, 80 and 60 percent water requirement as the main treatments, and three irrigation methods included fixed every-other- furrow, alternative every-other- furrow and every-furrow irrigation as the subsidiary treatments. Statistical analysis of the results of two years' data showed that treatment with 100% water requirement with every-furrow irrigation and treatment with 60% irrigation water requirement with fixed every-other-furrow had the highest and lowest yield, respectively. The highest water use efficiency was in 60 percent irrigation water requirement with a fixed every-other- furrow treatment and the lowest water use efficiency was related to the treatment with 100 percent irrigation water requirement with alternative every-other- furrow. The value of ky was obtained 0.8 for the total growth stage.