Title: Grain Yield and Nitrogen Use Efficiency of Mid-season <i>Indica</i> Rice Cultivars Applied at Different Decades
Abstract: Improvement in rice cultivars plays an important role in increasing grain yield. However, little is known about the relationship between yield and nitrogen use efficiency in mid-season indica rice cultivar improvement process. In this study, 12 typical cultivars(including hybrid combinations) applied in the production in Jiangsu Province during the last 70 years were used, and classified into four types of 1940–1950s, 1960–1970s, 1980–1990s, and after 2000(super rice) according to their application times. Three treatments of zero N(0N), 210 kg ha–1 N(MN) and 300 kg ha–1 N(HN) were designed. The results showed that grain yield and nitrogen use efficiency were progressively increased with the improvement of cultivars under each nitrogen rate. The super rice cultivars had a higher biomass and nitrogen accumulation, higher activities of root oxidation and nitrogen metabolic enzyme and higher leaf photosynthetic rate resulting in higher grain yield and nitrogen use efficiency when compared with any other types of cultivars. The root oxidation activity and photosynthetic characteristics of super rice were the peak at the heading stage, but sharp declined from heading to maturity, which could account for an important physiological reason for a lower filled-grain percentage of super rice. It would be an important approach to further increase grain yield of super rice through increasing root activity and leaf photosynthetic rate during grain filling.
Publication Year: 2015
Publication Date: 2015-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 6
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