EVALUATION OF WHEAT GENOTYPES FOR RESISTANCE TO LEAF RUST (Puccinia triticina) UNDER INOCULATED CONDITION

Abstract

The concept of this research program was to evaluate disease resistance capacity of wheat germplasm against leaf rust caused by Puccinia triticina during December 2016- March 2017 at WRC, Dinajpur. A total of 72 entries including resistant and susceptible checks were planted in lm long 2-row plots with 20 cm spacing between rows and 30 cm between entries in last week of December. Susceptible variety Morocco was planted in two rows after each pair of test lines and the nursery was surrounded by spreader rows of susceptible varieties. Test entries and spreader rows were inoculated by spraying with aqueous suspension of urediospores at booting stage of the crop (105 spore/ml) under natural inoculated field condition. Disease assessment was done between early and soft dough stages using modified Cobb scale on severity and infection types. Genotypes were graded into resistance category based on disease severity. From the present study nine genotypes showed high levels of resistance with zero percent (0%) infection that indicates the genotypes was completely immune to leaf rust. In this case, 14 genotypes showed 0.5% infection with reaction type‟s tMR, tMS and tMSMR which indicated slower disease development considered resistance category „R‟. Under scored the reaction type in 13 genotypes provided 10% infection recognizing MS, MSS, MSMR expressing moderately susceptible, moderately susceptible and moderately susceptible to moderately resistance where MR category achieved. After assessed nine genotypes indicated 20% infection including MS, MSS showed moderately susceptible and moderately susceptible to susceptible which included under resistance category „MR‟. Moreover four genotypes showed 30% infection which were MS reaction type displaced moderately susceptible which was in moderately resistance category „MR. Five genotypes showed 40 up to 50% including MS, MSS, S recognizing moderately susceptible, moderately susceptible to susceptible and susceptible. 90% severity with susceptible reaction was displayed in Morocco variety which placed with highly susceptible category „HS‟. All the selected genotypes flowered earlier 54-60 than the Shatabdi, BAW 1312, KALYANSONA and BARI Gom 31 genotypes 66-70 days which showed late heading. The lowest days of heading were recorded 54 days after sowing in BAW 1267 line and the highest days of heading were recorded in variety KALYANSONA 69 days. In this experiment the highest yield (178g/ plot) was recorded in BAW 1313 and the lowest yield (39g/plot) was found in variety of MOROCCO. BAW 1222, BAW1260, BAW1280, BAW1283, BAW1312, BORLAUG100, SAWYT304, BARI Gom 27 and BARI Gom 30 were showed higher resistance (zero percent infection) genotypes against leaf rust with higher yield potential (69-159g/plot) From the research findings it may be concluded that all the advanced lines were graded as resistant and moderately resistance to leaf rust infection where the above seven lines were completely free from leaf rust infection. VIII CONTE