Silage maize quality in different uses of Italian ryegrass and soil management methods after liming

The effects of lime application with multiple soil management methods and uses on dry matter (DM) yield and crude protein (CP) content of Silage maize cropping in succession with Italian ryegrass (ryegrass) from 2009 to 2014 in a southern Brazilian Oxisol were studied. The experimental design was completely randomized block in split-plot with four replications. The main plot treatments were the four soil management methods: conventional tillage (CT), minimum tillage (MT), no-tillage (NT) and chiseled no-tillage (CNT). The sub-plots treatments were the three uses of Italian ryegrass (ryegrass): cover crop (CC), silage (S), and grazing dairy heifers as part of integrated crop-livestock system (ICL). In all the years, the maize was sown approximately 30 days after the ryegrass desiccation with herbicide. In the medium-term (5 yrs.) after liming, soil management methods did not change DM yield and CP content in silage maize. The use of ryegrass for S and ICL did not change DM yield, but notably maintained or increased CP content in silage maize after liming. The use of ryegrass only as CC provided less measurable benefits than the combined production system of silage maize with ryegrass.     

Effect of encapsulated calcium carbide on dinitrogen,nitrous oxide,methane, and carbon dioxide emissions from flooded rice

Summary The efficiency of N use in flooded rice is usually low, chiefly due to gaseous losses. Emission of CH₄, a gas implicated in global warming, can also be substantial in flooded rice. In a greenhouse study, the nitrification inhibitor encapsulated calcium carbide (a slow-release source of acetylene) was added with 75, 150, and 225 mg of 75 atom % ¹⁵N urea-N to flooded pots containing 18-day-old rice (Oryza sativa L.) plants. Urea treatments without calcium carbide were included as controls. After the application of encapsulated calcium carbide, 3.6 g N₂, 12.4 g N₂O-N, and 3.6 mg CH₄ were emitted per pot in 30 days. Without calcium carbide, 3.0 mg N₂, 22.8 g N₂O-N, and 39.0 mg CH₄ per pot were emitted during the same period. The rate of N added had a positive effect on N₂ and N₂O emissions, but the effect on CH₄ emissions varied with time. Carbon dioxide emissions were lower with encapsulated calcium carbide than without. The use of encapsulated calcium carbide appears effective in eliminating N₂ losses, and in minimizing emissions of the greenhouse gases N₂O and CH₄ in flooded rice.     

Vanadium induced manganese toxicity in bush bean plants grown in solution culture

Seedlings of two bush bean cultivars (Phaseolus vulqaris L. cvs. Mn‐sensitive ‘Wonder Crop 2’ and Mn‐tolerant ‘Green Lord') were grown for 14 days in full strength Hoagland No. 2 nutrient solution containing 0.05 ‐ 2 mg L^‐1 of vanadium (V) as ammonium vanadate.

Increasing V concentration in the solution decreased total dry weight of both cultivars. Plant tops were stunted and leaf color became dark green at 1 ‐ 2 mg L^‐1 V, especially in ‘Green Lord’. Veinal necrosis similar to that of Mn toxicity was observed in the primary leaves of ‘Wonder Crop 2’ at 0.2 mg L^‐1 V or above, but not in those of ‘Green Lord’.

The V concentrations in the roots increased exponentially with increasing V concentration in the solution; however, V concentrations in the leaves and stems were not affected. The Mn concentrations in the primary leaves increased under the higher V treatment in ‘Wonder Crop 2'; but not in ‘Green Lord’. In contrast, Fe concentration in the leaves of ‘Wonder Crop 2’ decreased markedly with increasing V concentration in the solution. Enhanced Mn uptake and greater reduction of Fe uptake by ‘Wonder Crop 2’ may explain the incidence of V‐induced Mn toxicity.     

Construction of chromosomal segment substitution lines and genetic dissection of introgressed segments associated with yield determination in the parents of a super‐hybrid rice

Heterosis is a phenomenon whereby hybrids of inbred lines produce favourable phenotypes that exceed those of their parents. Traits of interest are higher yield and stronger stress tolerance. The two‐line super‐hybrid rice ‘Liangyoupei9’ (LYP9) shows superiority to both its elite inbred line ‘93‐11’ and ‘Pei'ai64s’ (‘PA64s’) parents and conventional hybrids. However, the genetic basis of its hybrid vigour, especially yield determination, remains elusive. In the present study, a set of 156 chromosome segment substitution lines (CSSLs) carrying overlapping segments from ‘PA64s’ in a genetic background of ‘93‐11’ were constructed and planted in six environments. Three major agronomic traits, viz. panicle length (PL), heading date (HD) and plant height (PH), and five yield‐related traits, viz. grain weight per panicle (GWP), number of grains per panicle (GPP), 1000‐grain weight (TGW), seed set (SS) and number of panicles of per plant (PPP), were evaluated over 3 years. Quantitative trait loci (QTL) analysis was conducted using a likelihood ratio test based on stepwise regression. Forty‐six putative QTL distributed on 11 chromosomes were detected in more than one year. Remarkably, GWP of four CSSLs carrying positive yield QTL outperformed the recurrent parent ‘93‐11’ by more than 15%, in at least two environments. These results indicate that CSSLs are effective in identifying yield‐associated traits, and lines harbouring such QTL will be rich in resources for future molecular breeding programmes.     

小麦收获前种子发芽敏感性配合力的研究

选用5个收获前穗发芽敏感性不同的白皮小麦亲本品种,进行双列杂交,研究了发芽敏感性的配合力。结果表明:小麦收获前种子发芽敏感性同时受加性和非加性基因效应影响,而加性基因效应起主导作用;亲本品种发芽敏感性的一般配合力存在极显著差异,杂交组合的特殊配合力和反交效应方差则有时显著,有时不显著;白皮小麦杂交当代种子,以     

苄嘧磺隆与尿素混用对陌上菜吸收除草剂的影响

14C-苄嘧磺隆与尿素混用,处理后1h,陌上菜[Lindernia procumbens (Krock.) Philcox]植株的14C放射性计数达到高峰.然而,14C-苄嘧磺隆单用,陌上菜植株的14C放射性计数随时间延长而缓慢增加,直至48h仍显著低于1h的除草剂与尿素混和的14C放射性计数.处理后24h,14C-苄嘧磺隆在陌上菜植株中的分配以根系最高,茎次之,叶最低.14C-苄嘧磺隆+尿素浸根,促进陌上菜植株对除草剂的吸收,但涂抹叶片时,无论单用还是混用,陌上菜植株均不吸收除草剂.     

Increased β‐cyanoalanine synthase and asparaginase activity in nitrogen‐deprived wheat exposed to cyanide

The β‐cyanoalanine pathway in plants detoxifies cyanide by assimilating this metabolic poison. Given the possibility that cyanide in soil could serve as an alternate source of nitrogen for plant nutrition, this study investigated whether nitrogen deprivation of wheat seedlings altered the activity of the first enzyme of the pathway (β‐cyanoalanine synthase) or asparaginase. The results suggest that ambient, nontoxic concentrations of soil cyanide may serve as an alternate source of nitrogen for plants under nitrogen‐limiting conditions.     

陆地型长绒棉主要经济性状遗传模式分析

选取两个遗传稳定的陆地型长绒种质系与 3个陆地棉品种按Griffing方法Ⅰ、模式Ⅰ全互交设计配成 5× 5共 2 5个杂交组合。对 9个经济性状进行调查 ,并建立Wr对于Vr的回归方程 ,测验“加性 +显性”模式的符合 ,制Wr对于Vr回归图 ,并估算各遗传参数。结果表明 ,纤维长度、纤维强度、马克隆值、籽棉产量、皮棉产量、单株铃数和单铃重遗传符合Hayman的“加性 +显性”模式 ,非等位基因间相互作用影响不显著。无论图解分析或平均显性度均表明纤维长度、纤维强度、马克隆值F1代为部分显性 ,加性效应方差在这 3个性状总遗传方差中占据相当重要的作用。分析性状中 ,与纤维长度、马克隆值和皮棉产量有关的增效基因 ,既有隐性也有显性 ,位点不同而有差异。纤维长度、纤维强度和马克隆值广义和狭义遗传力均较高。     

玉米优良杂交种豫玉22产量性状的遗传分析

以玉米优良杂交种豫玉22的F2∶3家系为材料,通过一年两点的田间试验，研究其产量性状的遗传特征，以期为提高玉米产量杂种优势的利用水平提供有益信息。结果表明,在8个穗部产量性状中，广义遗传力较高的为行数、穗长、出籽率、穗粗；在F1代和F2∶3家系中，杂种优势强的性状是穗粒重、行粒数、穗长，较弱的是出籽率和百粒重；     

250g／L氟磺胺草醚水剂对大豆田阔叶杂草的防治效果

[目的]研究250g/L氟磺胺草醚SL在吉林省区域内防治大豆田间杂草的效果。[方法]以250g/L氟磺胺苹醚SL为供试药剂,于2007年在吉林省大豆主产区进行大豆田除草药效试验。[结果]250g／L氟磺胺草醚SL对大豆田一年生阔叶杂草有良好的防除效果,而且对大豆生长安全,推荐用量300．0～375．0g／hm^2。[结论]该试验为250g／L氟磺胺草醚SL的进一步推广应用提供参考。