Drought and high temperature often occur simultaneously will eventually affect rice (Oryza sativa L.) yield and seed quality. The objective of the study was to compare the effects of high temperature (HT) and water limitation (WL) during seed development and maturation on yield component, seed quality, and amylose content in aerobic rice cv. MRIA. Two experiments were conducted concurrently in greenhouse with ⁓35/26℃ subjected to elevated HT and/or WL; 5 days 38/28°C at 10, 15, 29 DAA and/or HT; 7 days at 40/28℃ at 8 and 21 DAA with 12h photoperiod in control environment growth chamber. Both experiments were respectively harvested at physiological maturity of 31 and 35 DAA. Grain yielded from the irrigated plant declined from over 27% to below 18% between 15 and 29 DAA. Combination stresses resulted in greater reduction of grain yield than single stress. Late seed development (29 DAA) had no effect either on yield component or seed quality as well as produce a high concentration in amylase content (16.7%) with greater germination capacity (91%). The non-stress plant harvested at 21 DAA resulted the highest percentage of germinated seeds (97%) whereas the vigour index (VI) was reduced to 70.3% and 58.9% at 8 and 21 DAA respectively. Extended plant stress to 7 consecutive days incurred the highest VI with low concentration of amylose content. There was a linear relationship incurred between seed amylase content with germination capacity and VI, however, there was an inverse relationship (R2 = 0.19) between amylase content with VI from plant treated with (HT and/or WL) for 7 days. The present results confirmed that the avoidance HT and WL during early (10 DAA) and mid (15 DAA) seed development with short duration of stress (5 days) obtained better in yield component, enhanced the seed quality and amylose concentration. The combined HT and WL damaged seeds’ quality were more than each stress alone. Therefore, avoiding HT and WL can be practically applied by farmers by irrigating throughout the rice plant during histodifferentiation to save water usage during seed maturation.

The influence of effective microorganisms (EM), microbial inoculant containing yeasts, fungi, bacteria and actinomycetes was evaluated in field trials of Aerob 1 paddy cultivation in Jasin, Melaka. Aerobic paddy is a new way of rice cultivation in areas where water resources have been scare and affected by the climate change. As water shortage and climate change is becoming severe, the technology of growing rice with aerobic rice systems need to be further refined or developed to ensure the quality of rice production in water-short areas. The objective of this study was to determine the effect of additional EM on the growth pattern, and to evaluate the efficiency of EM uptake on the aerobic plant. This experiment was carried out by using random controlled Randomized Controlled Block Design (RCBD) consisted of three treatments with two replications in four blocks. Aerobic seed cv. Aeron1 was used as planting materials and has been applied by three different treatments of EM during vegetative growth. The treatment for this study was T1 = 1.8 g NPK with urea (control) while T2 was 1.8 g NPK and T3, with 0.9 g NP with 100 mL of EM respectively during 15 (early vegetative stage) and 45 DAS (late vegetative stage). The RCBD experimental design was used with two replications in each treatment in four blocks. There are three series of harvesting (35, 50 and 60 DAS) was conducted throughout this study. The growth parameter studied was shoot and root dry biomass, number of tillers, RGR at each of harvesting. Our finding revealed that the application of EM did not improve plant growth parameter but the growth pattern of T2 and T3 showed steady improvement, although not significant compared to T1. The application of EM at different growth stages did not enhance the relative plant growth rate of Aeron 1 under aerobic condition, but in comparison to T1 and T2, T3 treatment with 50% reduction of NPK and EM could significantly reduce the cost of land management and fertilizer.