Genotype evaluation under SRI and normal cultivation

Genotype evaluation under SRI = and normal cultivation

P. Narsim= ha Reddy, T. Dayakar Reddy, Ch. Surender Raju, S. Vanisree, Narendra Kulkarni, T. Ratna Sudhakar, M. Srinivasa Ra= ju and V.Ravindra Babu

Rice Section, Agicultur= al Research Institute, ANGRAU, Rajendranagar, Hyderabad 500 030= , AP

&= nbsp; With extensive adoption of high yielding varieties, the economically exploitable yield potential of rice has reached a plateau in irrigated rice system. Eve= ry such technology has its own potential boundaries beyond which yield levels cannot be increased. Any other method which can break the yield ceiling is desirable to meet the food grain production targets.

&= nbsp; Therefore, during kharif<= /i> 2003, 2004 and 2005 an experiment= was conducted on the System of Rice Intensification (SRI) along with normal met= hod of cultivation, using four different high yielding popular verities and one hybrid. The data pertaining to 50% flowering, productive tillers, plant hei= ght and grain yield were recorded. The results indicated that the varieties significantly differed in grain yield response under both normal and SRI cultivation. The hybrid KRH-2 recorded the hig= hest grain yield under SRI as well as normal method of cultivation followed by RNR-23064, Early Samba, Krishna Hamsa and Rajendra over the years. The varieties differed among themselves for grain yield but recorded a consistent performance under both= the methods of cultivation. Overall yield performance over the years, though varied but not significantly, suggested suitability and consistency.<= /o:p>

        &= nbsp;   Among the methods of cultivation, SRI method recorded significantly superior yiel= ds than the normal method in all the years under test. Similar trend was obser= ved for yield attributing characters also.

        &= nbsp;   Based on the results obtained, the hybrid KRH-2 and the variety RNR-23064 perform= ed well under SRI method of cultivation recording grain yield of 8.954 and 8.5= 10 t/ ha, respectively, while under normal cultivation these gave 6.895 and 6.= 432 t/ha. Thus there was a yield advantage of 29.8 and 32.3 per cent, respectiv= ely. The early duration variety Rajendra was found t= o be the best suited for SRI method with 34.1 per cent yield advantage.

        &= nbsp;   Though the incidence of early stage insect pests viz. thrips, whorlmaggot was moderately high, their damage did not= have influence on tiller production. In SRI, the stem borer incidence was less (= 10.4 %) as compared to that in normal planting (33.6 %) at 85 DAT in Rajendra variety.

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