Genetic variability of heat tolerance, and its effect on yield and fibre quality traits in upland cotton (Gossypium hirsutum L.)

Global temperature is rising because of increasing concentrations of CO₂ and other greenhouse gases (e.g. methane, nitrous oxide, etc.) in the atmosphere because of the excessive use of fossil fuels. High temperature causes heat stress which reduces crop productivity. The development of heat-tolerant varieties is feasible and will help mitigate the effects of climate change. Fifty-one cotton accessions were screened in heat-stressed and non-stressed conditions in the glasshouse and field. Relative cell injury percentage (RCI %), a measure of cell membrane thermostability (CMT), was used to assess heat tolerance. Heat-tolerant accessions had more stable yield and yielded more seed cotton with better quality fibre than the heat-intolerant accessions across four environments. The responses of the 51 accessions to all four environments for the measured traits were strongly associated. RCI % of the accessions and hybrids was strongly and negatively associated with yield and fibre traits. CMT was concluded to be a useful technique for identification of heat-tolerant cotton.     

寒地早粳品种稻瘟病抗性与产量性状的关系

采用寒地早粳近5年审定和参加黑龙江省区域试验、生产试验的水稻品种316个为材料,对稻瘟病抗性与水稻生育特性、产量性状的相关关系进行了研究。结果表明,无论在人工接种还是在自然感病条件下,寒地早粳品种的叶瘟、穗颈瘟与生育日数、活动积温呈极显著负相关,平均相关系数分别达到-0.2647、-0.1796和-0.2090、-0.1743;叶瘟、穗颈瘟与穗长呈极显著负相关,平均相关系数为-0.3027和-0.2765,而与平方米穗数呈显著正相关,平均相关系数达到0.1953和0.1481,穗颈瘟与产量呈显著负相关,相关系数为-0.1792。表明在寒地稻作区生育日数越长、活动积温越高叶瘟和穗颈瘟的发病越轻,平方米穗数越多稻瘟病越重,品种抗病性越强产量越高。因此,通过对品种生育性状的适当选择,在寒地稻作区完全可以选育出既高产又抗病的水稻新品种。     

长期施用含SO42- 肥料对水稻农艺性状及产量影响

为了研究长期施用含SO4=肥料对水稻水稻农艺性状及产量的影响,对红壤地区农业持续发展和科学研究提供原创性的理论依据,刘更另院士于1975年开始在湖南祁阳官山坪中国农业科学院红壤实验站布置了肥料定位试验。试验设三个处理,即：处理一：SO4=,采用含SO4=化肥：(NH4)2SO4 + K2SO4 + 过磷酸钙。 处理二： Cl- ,采用含Cl- 化肥：NH4Cl + KCl + KH2PO4;处理三：隔离区（CK）。施用化肥NPK。即：尿素 +过磷酸钙+ 氯化钾。 三个处理NPK用量相同。通过32年的长期研究,结果表明：1.长期施用含SO4=肥料对水稻产量没有多大影响;2.长期施用含SO4=肥料能够提高水稻生物产量。据1982-2007年26年的总产量（生物产量）统计,SO4=处理（488653.5kg/hm2）,比CK处理（483862.1 kg/hm2）高4791.4kg/hm2,比Cl-处理（477262.5kg/hm2）高11391.0 kg/hm2。3. 长期施用含SO4=肥料能够增加水稻有效穗,但结实率和千粒重较低。     

检验用砻谷机研制报告

在"十五"科技攻关计划项目<新型检验用砻谷机、碾米机及便携式米质判定仪开发>课题研究中,成功地解决了实验室检验用砻谷机在稻谷脱壳后谷糙分离效果和易损件的耐用性等关键性问题;设计出科学合理的糙米分离系统,筛选出弹性和硬度均适宜的新型耐磨材料作砻谷机的胶辊材料,从而大大提高了产品易损件的耐用性和稻谷的一次性脱壳率,降低了脱壳过程中产生的糙米破碎率.检验用砻谷机,具有小型轻便、结构简单、噪音小、操作方便、经久耐用等特点,适用于各级实验室的稻谷品质检验.     

陆稻苗期抗旱性鉴定指标筛选与评价

为筛选出陆稻苗期抗旱性鉴定指标,以24个云南陆稻品种为材料,采用反复干旱存活率作为标准,分析各测定指标与抗旱性的相关关系并对供试品种的抗旱性进行综合评价。结果表明,心叶下倒1叶长、心叶下倒2叶长、心叶下倒2叶宽、根干重和根冠比等5个形态指标的相对值与反复干旱存活率呈显著或极显著的相关性,可作为苗期抗旱性鉴定的形态指标。以反复干旱存活率为因变量,5个综合指标为自变量建立的回归方程对24个供试品种的抗旱性进行预测,其结果与芽期抗旱鉴定呈显著相关关系。     

基于MaxEnt模型湖南双季稻种植气候适宜性分布研究

通过查阅了相关文献资料,选取了适宜湖南水稻种植分布8个潜在的气候因子和湖南17个双季稻农业气象观测站点位置信息,利用MaxEnt模型,构建了湖南杂交水稻潜在种植分布与气候因子关系模型,得出影响湖南水稻种植的主要气候因子,以及湖南水稻适宜性种植分布区域。结果表明：10~22℃活动积温、4—10月日照时数、稳定通过22℃持续日数、4—10月降水量为影响种植湖南双季杂交稻主导气候因子。并进一步通过得到的主导气候因子,采用MaxEnt模型再次进行湖南双季杂交水稻适宜种植性分区,将湖南省双季稻制种植分布划分为：最适宜区、适宜区、低适宜区和不适宜区。本研究的主要目的是在省级层面上利用MaxEnt模型筛选影响湖南水稻种植主导气象因子,并对湖南水稻适宜性种植分布做了不同等级划分,为优化湖南双季杂交稻生产布局、改进种植制度和确保粮食生产安全提供了一定气象参考依据。     

抚仙湖北部农田区不同施肥对水稻产量、氮素吸收及利用率的影响

针对抚仙湖北部农田区的蔬菜施肥过量导致土壤养分残余量大,会对后作水稻施肥造成影响的问题,采用田间小区开展不同施肥试验研究。结果表明,砂壤土和粘壤土在施氮量为150~360 kg/hm²范围内,水稻植株氮素积累量随着施氮量的增加而提高,而增加的氮素积累量主要表现在茎叶部位;穗肥施用氮肥可提高籽粒氮素积累量。水稻氮肥吸收利用率和产量,砂壤土以施氮255 kg/hm2时最高,分别为45.1%和10594 kg/hm²;而粘壤土施氮150~360 kg/hm²之间,氮肥吸收利用率为20.9%~22.4%之间,产量为10486~10596 kg/hm2之间;当对砂壤土和粘壤土的水稻穗肥施用氮肥时,水稻氮肥吸收利用率（分别为42.8%、23.5%）和产量（分别为10445 kg/hm²、10564 kg/hm²）最高。水稻的氮素收获指数、氮肥农学利用率、氮肥生理利用率及氮肥偏生产力,均以砂壤土明显高于粘壤土,且随着施氮量的增加而显著下降。蔬菜后作水稻施氮量以150~255 kg/hm²范围为宜,氮肥分基肥50%+分蘖肥30%+穗肥20%施用     

南方丘陵区水资源系统承载脆弱性动态演变特征研究——以衡阳盆地为例

为研究衡阳盆地农村水资源系统脆弱性动态演变问题,主要通过遥感(RS)获取研究所需数据,采用地理信息系统(GIS)空间建模和空间分析方法,以衡阳盆地为例,构建提取水资源系统承载脆弱性变化信息的数学模型,生成水资源系统承载脆弱性变化图层,分析近20年来衡阳盆地水资源系统承载脆弱性变化的时空特征,并进行趋势分析。结果表明：（1）近20年来,衡阳盆地水资源系统承载脆弱性整体上变得更为脆弱,26.1%的区域承载脆弱性指数明显增大,脆弱性指数变小的区域则微乎其微。（2）脆弱性指数区域分异明显,整体呈“中强外弱、南强北弱”的分布格局。（3）从脆弱性指数演变的时段上来看,水资源承载脆弱性总体上呈增强趋势,其中,尤以2005—2010年时段的变化最为明显。（4）从变化趋势来看,区域水资源承载脆弱性指数主要表现为稳定型和波动型2种趋势,单调增大和单调减小型所占比例极小。     

预处理对稻草秸秆纤维素酶解产糖及纤维素木质素含量的影响

采用酸处理、碱处理和机械粉碎3种方法对稻草秸秆进行预处理。探讨3种预处理方法对稻草秸秆酶解产糖以及纤维素、木质素含量的影响。结果表明,3种预处理都可以较为有效地提高稻草秸秆的酶解产糖率。经酸处理、碱处理和机械粉碎处理后,稻草秸秆的最高酶解产糖率分别为9.25%,33.16%和10.64%,分别约为对照的3.4倍、12.0倍和4.0倍。酸处理和碱处理可以去除部分杂质,达到纯化稻草秸秆的目的,提高纤维素酶的作用底物——纤维素的比例,从而提高酶解产糖率;而机械粉碎则主要是通过提高酶反应的接触面积来达到提高酶解产糖率的作用。     

Water Relation, Photosynthetic Ability and Growth of Thai Jasmine Rice (Oryza sativa L. ssp. indica cv. KDML 105) to Salt Stress by Application of Exogenous Glycinebetaine and Choline

Rice reportedly possesses a very low capacity to accumulate glycinebetaine (Glybet), but may be accumulated by the exogenous application of Glybet or Choline (Cho) as an alternative way to improve its salt‐tolerant ability. The aim of this research was to determine whether Glybet accumulation could be induced in Thai jasmine rice by the exogenous application of Glybet and Cho, and to determine the effects of Glybet and Cho treatment on various growth parameters of seedlings cultured under salt‐stress conditions. Thai jasmine rice seeds were aseptically germinated in vitro on solidified Murashige–Skoog media, supplied with either Glybet or Cho in the culture media for 12 days and then treated with 342 mm NaCl (salt stress) for 4 days. GlyBet content, water relation, photosynthetic capabilities and growth characteristics of salt‐stressed seedlings were measured. The addition of Glybet or Cho to plant culture media containing 342 mm NaCl resulted in increased accumulation of Glybet in rice seedlings. Increased Glybet accumulation was strongly associated with a high efficiency of water usage (r = 0.96), which in turn correlated with increased maximum quantum yield of PSII (F_v/F_m) (r = 0.86). Moreover, the pigment concentrations of seedlings cultured under salt stress were maintained by a function of Glybet, led to high efficiency of photochemical and non‐photochemical quenching of PSII as well as to exhibit on net photosynthetic rate. Thus, our results suggest that the addition of either Glybet or Cho to the plant growth media can improve growth performance under salt stress conditions by increasing the salt tolerance of Thai jasmine rice. The exogenous application of Glybet and/or Cho to culture media may be an effective method of improving resistance to salt stress via the promotion of Glybet accumulation with in rice seedlings.