A study was undertaken to investigate the variability among lowland rice cultivars and the mode of gene action of aluminum (Al) toxicity tolerance in rice. Pregerminated seeds were grown in a nutrient solution containing 30 ppm Al and in normal nutrient solution, and relative root length (RRL) was determined at the 14-day-old stage to characterize genotypes for tolerance. Sixty-two traditional rice cultivars grown on lowland acid sulfate soil areas of Asia and West Africa were tested. Tolerant varieties 'Azucena', 'IRAT104', and 'Moroberekan', moderately sensitive 'IR29' and 'IR43', and sensitive 'IR45' and 'IR1552' were used to investigate the genetics of tolerance by diallel analysis. Of the 62 cultivars tested, only 3 were found to be sensitive to A l toxicity. Among the tolerant cultivars identified, 11 ('Siyam Kuning', 'Gudabang Putih', 'Siyam', 'Lemo', 'Khao Daeng', 'Siyamhalus', 'Bjm-12', 'Ketan', 'Seribu Gantang', 'Bayer Raden Rati', and 'Padi Kanji') were found to possess higher levels of tolerance than the improved tolerant upland cultivar 'IRAT104'. Diallel analysis revealed that high RRL is governed by both additive and dominance effects with a preponderance of additive effects. The trait exhibited partial dominance, and one group of genes was detected. Heritability was high, and environmenal effects were low. Findings suggest that when breeding for A1 toxicity tolerance, selection can be made in early generations. The pedigree method of breeding would be suitable. Combining ability analysis revealed the importance of both general combining ability (GCA) and specific combining ability (SCA) in the genetics of A1 toxicity tolerance in rice. GCA was more prevalent than SCA. Tolerant parens 'Azucena', 'IRAT104', and 'Moroberekan' were the best general combiners. The presence of reciprocal effects among crosses suggested the proper choice of parents in hybridization programs. Results indicated that 'Azucena', 'IRAT 104', and 'Moroberekan' should be used as the female in crosses for A1 toxicity tolerance.
Foxtail millet (Setaria italica (L) P Beauv) falls on the category of underutilized crops in Nepal and mainly cultivated in Karnali region of the country. It is hardy crop and considered as one of the potential crops for future food security with respect to climate change. Five accessions of Nepalese foxtail millet were purposefully selected for evaluation of the agromorphological characteristics. Foxtail landraces from Dolpa, Mugu, Bajura, Bajhang and Lamjung districts of Nepal were evaluated at Khumaltar, Lalitpur, Nepal during 2010. The plot size was 1m 2 and there were five samples. Days to heading and days to maturity varied from 33-56 and 59 to 87 days after germination respectively. Similarly, flag leaf length/breadth ratio, flag leaf sheath length, ligule length, peduncle length, peduncle exertion and plant height varied from 3.84-10.90, 5.47-9.84 cm, 0.1-0.2 mm, 10-22.57 cm, 2.7-13.58 cm and 41.67-120 cm, respectively. Fruit and apiculus color varied from straw to black. All accessions were actively growing with very slight lodging. Similarly, the thousand grain weight varies from 1.064 g to 2.172 g. This variation is useful in foxtail millet breeding program. Similarly, the significant correlation between thousand kernel weight and total basal tiller (r=-0.975) showed that foxtail millet lines with low tillering ability is better for yield enhancement.
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