Introduction Studi Genetik Toleransi Genangan Pada Padi

INPARA 4 did not perform well under stagnant flooding after submergence treatment Singh et al. 2009; Singh et al. 2011. In addition to the increasing of plant height, reduction in the number of tillers is a response to stagnant flooding stress Collard et al. 2013. Stagnant flooding reduced number of productive tillers, with average of 25 and genotype range of 3-46 Table 3.2. Table 3.2 Plant height and number of productive tillers of rice under normal and stagnant flooding SF condition Genotype Plant height cm Number of productive tillers Normal SF SFN Mean Normal SF SFN Mean INPARA 3 114b 129b 113 114b 15 9 59 12c INPARA 7 113b 125bc 110 112b 19 15 80 17ab IRRI 119 129a 136a 106 118a 17 13 77 15b INPARA 4 91e 117de 128 110d 19 19 97 19a INPARA 5 101d 110f 109 105d 17 15 88 16b INPARI 30 113b 123bc 109 111bc 23 12 54 18ab IR 64 101d 114ef 113 107d 21 17 79 19a IR 42 106cd 122cd 116 111c 23 16 72 20a Ciherang 111bc 125bc 113 112bc 20 15 72 18ab INPARI 29 115b 128bc 112 114b 17 13 76 15b Mean 109 123 113 19 14 75 Different letter in the same column indicate statistical significant P0.05 The decrease of filled grains number per panicle was moderately low. Some genotypes even have higher number of filled grains in stagnant flooding stress than normal conditions. This was probably caused by assimilate substitution from number of reduced productive tillers to the number of filled grains, as shown by INPARA 3, INPARI 30, and Ciherang. Increased number of panicle accounted largely for grain yield response to increased CO 2 Ziska et al. 1997; Baker et al. 1990, 1992. Increased tillering is not desirable characteristic in high yielding irrigated condition as it increased susceptibility to lodging. Thus selecting cultivar which can channel increased resources into converting juvenile spikelets into grains rather than developing extra tillers must be a priority for condition of increased atmospheric CO 2 Sheehy et al. 2001. Table 3.3 Grain yield components of rice under normal and stagnant flooding SF condition Genotype Number of filled grains Weight of 1000 grain g Normal SF SFN Mean Normal SF SFN Mean INPARA 3 104 114 110 109a 27cd 26 97.0 26.2bc INPARA 7 94 89 94 91abc 29b 28 96.3 28.1ab IRRI 119 99 92 93 95ab 30a 30 97.1 29.9a INPARA 4 76 100 131 88bc 21e 25 118.8 23.1d INPARA 5 100 101 101 101ab 28bc 25 90.7 26.4bc INPARI 30 75 97 129 86bc 27cd 27 99.7 26.6bc IR 64 91 78 86 84bc 26d 27 101.2 26.3bc IR 42 75 72 96 74c 21e 23 109.5 22.4d Ciherang 81 103 127 92ab 27cd 25 92.8 25.9c INPARI 29 94 90 95 92ab 27cd 27 101.6 26.8bc Mean 89 93 105 26 26 99.8 Different letter in the same column indicate statistical significant P0.05 The average decrease of grain yield from normal to stagnant flooding stress was 27 . Meanwhile yield decreasing of every genotype was ranged from 20 to 41 . Genotypes which have greater decreasing of grain yield were INPARI 29 and INPARA 3. Nevertheless, it is necessary to have further experiments in several seasons to confirm the tolerance Table 3.3. Table 3.4 Grain yield of rice under normal and stagnant flooding SF condition Genotype Grain yield tha Normal SF SFN Mean INPARA 3 6.23 3.86 61.96 5.05cd INPARA 7 6.83 5.02 73.50 5.93ab IRRI 119 6.57 4.79 72.91 5.68abc INPARA 4 6.38 4.99 78.21 5.69abc INPARA 5 5.81 4.43 76.25 5.12cd INPARI 30 6.89 5.32 77.21 6.11a IR 64 7.42 5.35 72.10 6.39a IR 42 5.10 4.07 79.80 4.59d Ciherang 6.86 5.49 80.03 6.18a INPARI 29 6.49 3.84 59.17 5.17bcd Mean 6.46 4.72 73.03 Different letter in the same column indicate statistical significant P0.05

3.3.2 Genotype and Water Regime Interaction on Morphological Traits

Effect of water regime was significantly different on stem length, stem diameter, and length of leaf blade. Meanwhile effect of genotype was significantly different on all observed traits. Interaction of water regime and genotype was only significantly different on width of leaf blade, panicle exertion, and length of panicle.