Improving Quantitative and Qualitative Characteristics of Wheat (Triticum aestivum L.) through Nitrogen Application under Semiarid Conditions

Nitrogen(N),the building block of plant proteins and enzymes,is an essential macronutrient for plant functions.A field experiment was conducted to investigate the impact of different N application rates(28,57,85,114,142,171,and 200 kg ha^(−1))on the performance of spring wheat(cv.Ujala-2016)during the 2017–2018 and 2018–2019 growing seasons.A control without N application was kept for comparison.Two years mean data showed optimum seed yield(5,461.3 kg ha^(−1))for N-application at 142 kg ha^(−1) whereas application of lower and higher rates of N did not result in significant and economically higher seed yield.A higher seed yield was obtained in the 2017–2018(5,595 kg ha^(−1))than in the 2018–2019(5,328 kg ha^(−1))growing seasons under an N application of 142 kg ha^(−1).It was attributed to the greater number of growing degree days in the first(1,942.35°C days)than in the second year(1,813.75°C).Higher rates of N(171 and 200 kg ha^(−1))than 142 kg ha^(−1) produced more number of tillers(i.e.,948,300 and 666,650 ha^(−1),respectively).However,this increase did not contribute in achieving higher yields.Application of 142,171,and 200 kg ha^(−1) resulted in 14.15%,15.0%and 15.35%grain protein concentrations in comparison to 13.15%with the application of 114 kg ha^(−1).It is concluded that the application of N at 142 kg ha^(−1) could be beneficial for attaining higher grain yields and protein concentrations of wheat cultivar Ujala-2016.

Correlation Analysis of SPAD Value with Chlorophyll Content and Economic Yield Traits of Brassica napus L.

[Objective] The aim was to compare differences of SPAD value, chloro- phyll content, agronomic characters, economic characters and yield traits to analyze correlation of SPAD value with other indices and establish regression functions. [Method] Based on 34 Brassica napus L. varieties, SPAD value, chlorophyll content, agronomic characters, economic characters and yield traits were measured and re- gression functions were established according to correlations. [Result] SPAD value, chlorophyll content, agronomic and economic characters and yield traits all achieved significant level in differences among 34 varieties. Specifically, SPAD value was of extremely significant correlation with chlorophyll a and b, total chlorophyll and carotenoid, and the correlation from high to low was chl-b〉chl-z〉chl-a〉chl-x. SPAD value was of significantly positive correlation with total pod number per plant, plant height, seed number per pod, yield per plant and harvest yield, and of insignificant correlation with branch point height, effective branch number, pod density of main stem, and pod length. [Conclusion] It is simple and rapid to predict chlorophyll con- tent, economic characters and yields of Brassica napus L. with SPAD value and re- gression functions.

Effects of Plant Density on the Economic Yield and Agronomic Characters of Perilla frutescens L.

Perilla frutescens L. is a traditional medicinal plant in china. In recent years, with more and more attention is paid to the nutritional and health values of Perilla frutescens L, it has become a potential medicinal and edible crop. Two Per- ilia frutescens cultivars, Qisu No.1 （oil type） and Qisu No.3 （leaf and seed-using type）, bred by Rapeseed Research Institute of Guizhou Academy of Agricultural Sciences, were used as test material for studying the effects of different planting density on the economic yield and agronomic characters of Perilla frutescens L. under moderate fertility level. The results showed the variation tendency of agro- nomic characters with the change of planting density was similar for the two Perilla frutescens cultivars. Among them, the plant height, main-stem nods, first effective branch length, first effective branch height, spikes per plant, and yield per plant were negatively related to the planting density; and main spike length and main- spike grains were positively related to the planting density. The effects of planting density on kilo-grain weight were not significant. The yield of the two cuitivars all increased first and then decreased with the increase of planting density. The re- gression analysis of planting density versus yield of Perilla frutescens L. was per- formed for obtaining the regression equations （Qisu No.l： y=54.046 5＋96.777 lx- 45.719 8x2, r=0.999 4; Qisu No.3：y=38.717 6＋42.111 3x-16.757 7x2, r=0.999 8）. Based on the regression equations, the optimal planting density for Qisu No.1 was 158 745 plants/hm2 with peak yield of 1 578.90 kg/hm2, and for Qisu No.3 was 188 745 plants/hm2 with peak yield of 977.55 kg/hm2. Under the optimal planting density, Qisu No.3 could also harvest 3 000 kg/hm2 of Perilla frutescens dry leaves and 2 400 kg/hm2 of Perilla frutescens stems. This research would provide an important reference for the promotion, high-yield cultivation and comprehensive utilization of Perilla frutescens L.

Effects of Fenaminosulf on Yield and Benefit of Single Cropping Zizania latifolia

[Objective]The paper was to normalize the application of fenaminosulf in single cropping Zizania latifolia. [Method]Effects of spraying periods,different concentrations and spraying times of fenaminosulf on yield and output value of single cropping Z. latifolia were studied.[Result]In some regions where single cropping Z. latifolia could be harvested twice per year,fenaminosulf significantly promoted formation of swollen gall,and advanced the harvest period for about 50 d. Application of 0.5 g/L（ a.i.） fenaminosulf at 150,160 and 175 d post transplanting promoted swollen gall formation and enhanced the yield of Z. latifolia.In normal single cropping Z. latifolia growing regions,once application of fenaminosulf obviously advanced harvest period and improved yield and benefit of Z. latifolia,but with the increasing frequency of use,yield and benefit of Z. latifolia decreased significantly.[Conclusion]It is recommended that 1.0 g/L（a.i.） fenaminosulf can be applied for just once at 40-60 d post transplanting of Z. latifolia.