Abstract

Continuous cultivation of dry seeded rice in addition to adverse environmental factors make the rice soils deficient of nitrogen more than any other essential nutrient. The study was conducted under greenhouse conditions in pots by varying soil N during seedling growth. Six cultivars with diverse genetic background, CL152, R4100412, Antonio, Bowman, Nipponbare, and Rex, were seeded in 6 × 12 inch PVC pots filled with 3:1 (sand: soil) as the rooting medium. All plants were irrigated with full-strength Hoagland nutrient solution, delivered three times for 28 days after sowing. Then, half the plants in each cultivar were supplied with 100% of control nutrient solution minus N for another 4 weeks. Agronomic, physiological and root parameters measurements recorded at optimum interval. Cumulative indices were calculated by summing each response index value as a ratio of treatment by control values. Cultivars were classified based on total cumulative N stress response index (TCNSRI), the sum of all the traits measured, into different groups based on mean and standard error. The reductions in most of the measured traits were less in CL152 and R4100412 than other rice cultivars to soil N stress. Based on total cumulative N stress response indices, the cultivars were classified. The cultivar R41004122 was identified as tolerant, CL152 as intermediate, and Antonio, Bowman, Nipponbare and Rex were sensitive to soil N stress. The identified soil N stress tolerant and intermediately tolerant cultivars will be useful to breeders to develop new genotypes and farmers to select cultivars best suited for dry seeded rice.

抽象的

除不利的环境因素外，连续播种稻米的水稻种植比任何其他必需营养素都使稻米土壤缺乏氮。该研究是在温室条件下的盆栽中，通过在幼苗生长过程中改变土壤氮素来进行的。将六个具有不同遗传背景的品种CL152，R4100412，Antonio，Bowman，Nipponbare和Rex播种到6×12英寸PVC盆中，该盆中装有3：1（沙子：土壤）作为生根培养基。所有植物均用全强度的Hoagland营养液灌溉，播种后28天分3次递送。然后，向每个品种的一半植物再供应100％的对照营养液减去N，持续4周。以最佳间隔记录农艺，生理和根系参数。通过将每个响应指标值相加，得出治疗指标与对照值之比，从而计算出累积指标。根据总累积N胁迫反应指数（TCNSRI）（测得的所有性状的总和）将品种分类为基于均值和标准误差的不同组。在土壤氮胁迫方面，CL152和R4100412的大多数测得性状的下降均少于其他水稻品种。基于总的累积N个胁迫响应指数，对品种进行分类。鉴定为R41004122耐性品种，CL152为中等耐性品种，Antonio，Bowman，Nipponbare和Rex对土壤氮胁迫敏感。鉴定出的耐氮胁迫和中度耐旱的栽培品种将有助于育种者开发新的基因型，并帮助农民选择最适合于旱稻的栽培品种。