Evaluation of some rice quantitative characters and blast resistance under different nitrogen fertilizer levels in some promising lines [electronic resource].

Includes references.

The main objectives of breeding program produced promising lines with high grain yield, resistant to blast and grain quality. Rice blast caused by Pyricularia oryzae cav is the most important rice diseases in Egypt and could cause a significant yield reduction. The present research was carried out at the farm of Rice Research and Training Center (RRTC), Sakha, Kafr ElSheikh, Egypt, during eight successive seasons from 2003 to 2010. Three crosses of rice; (Giza 177x HR 5824-8-3-2-3) cross 1, (Sakha 101 x HR 5824- 8-3-2-3) cross 2, (GZ 5310-20-3-3 x Sakha101) cross 3 were evaluated in 2005. From cross 1 the expected ratio 15:1 chi-square x2 value 0.48 with probability value 0.5 to 0.75 indicated that the presence of two pairs of complementary dominance resistance genes for blast resistance. From BC1 and BC2 the expected ratio was 3:1 indicated the presence of one pair of dominance resistance gene controlling blast resistance. From cross 2 the same trend for F2, BC1 and 8C2 generations for expected ratio and dominance resistance genes. For cross 3 the expected ratio in F2, BC1 and BC2 were 1:3 and 3:13 respectively indicated the presence of different pairs of resistance genes controlling blast resistance. In 2008, 12 lines were evaluated under field conditions for some agronomic traits and blast reaction under blast nursery test and artificial inoculation with different races in greenhouse. The best promising line was pL-4-4 out from cross 1, gave the short stature 97 cm, early maturing 121 day, high yielding 10.14 t/ha, resistant to blast and good grain quality. From cross 2 the best elite was SP-5-70 which gave plant height 96 cm, late duration 140 day, high yielding more than 12 t/ha. high 1000-grain weight. good grain quality and resistant to blast disease. BY-6-20 derived from cross 3 was excellent promising line for some yield components and blast reaction. For blast resistance under different locations and artificial inoculation in greenhouse. Giza 177 and GZ 5310-20-3-3 highly resistant but Sakha101 and HR 5824-B-3-2-3 were susceptible to rice blast at seedling and adult stages. In cross 1 exhibited a wide range of resistance for blast under different stages in various locations. The best line PL-4-4 was highly resistant to blast under field conditions at both seedling and adult stages. also under artificial inoculation with specific races at seedling stage. The cross 2 exhibited the most susceptible derived lines to blast under all conditions, but the best line was SP--6-70, highly resistant. For cross 3, the line BY-6-20 was highly resistant to blast under field and greenhouse conditions. Finally, In 2009 and 2010 seasons the best lines were evaluated under different nitrogen levels i.e., 0, 55, 110 and 165 Kg N/ha in split plot design for growth yield and some its components. Three promising lines; PL• 4-4. SP-S-70 and BY-6-20 in addition to Sakha101 as a commercial check variety under four N levels. Significant differences were detected among the three promising lines and Sakha101 in growth, grain yield and its components in the two seasons. Sakha101 and promising lines; BY-6-20 and SP-6-70 were superior in LAI, Flag leaf area, No. of panicles/m2 No. of filled grains/panicle and grain yield t/ha., While, BY-6-20 gave the heavier 1000- grain weight and panicle weight. Increasing nitrogen levels significantly improved growth, yield and its components. Each unit increase in nitrogen levels led to a significant increase in all these traits. The interaction between promising lines and nitrogen levels Significantly affected LAt, flag leaf area. panicle number/m2 and grain yield. Both the promising lines BY-6-20 and SP- 6-70 recorded high grain yield and can be recommended with package of improved management practices for general cultivation. The promising lines BY-6-20 and SP-5-70 was superior in terms of rough rice yield at higher N levels. Its is extremely important to note that BY-6-20 and SP-6-70 matures approximately 10 days earlier than Sakha101. Keywords: Rice, Mean performance, promising lines, Blast. Pyricularia oryzae, Nitrogen Levels.

Summary in Arabic.

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