Intercropping field crops between rows of Leucaena leucocephala under rainfed conditions in northern India

A field study was conducted for six years (1981–1986) on sandy loam soil on intercropping hedgerows of Leucaena leucocephala (Lam) de Wit. with three field crops viz. maize (Zea mays L), black gram (Vigna mungo L) and cluster bean (Cyamopsis tetragonoloba L Taub.). In treatments 1 and 2 Leucaena hedges were planted as pure crops at close (25 cm × 75 cm) and wide (25 cm × 375 cm) spacings. In treatments 3, 4 and 5 the three field crops were intercropped between the hedgerows of Leucaena at the wide spacing, and in treatments 6, 7 and 8 the field crops were raised as pure crops. Leucaena was topped to 75 cm each time it attained a height of 175 cm. The pure crop of Leucaena at close spacing produced an average, over the six years, of 34 t ha⁻¹a⁻¹ of green fodder and 9.4 t ha⁻¹a⁻¹ of air dry fuelwood. The Leucaena at wide spacing produced 18.9 t ha⁻¹a⁻¹ of green fodder and 6.3 t ha⁻¹a⁻¹ of fuelwood. Intercropping with field crops decreased the yield of green fodder and fuelwood. The yield of all the field crops was less when raised as intercrops than as pure crops. Mean maximum net returns were obtained from intercrops of Leucaena and cluster bean (Rs 3540 ha⁻¹a⁻¹) which were significantly higher than the returns from pure crop of Leucaena at wide spacing but similar to the returns from pure crops of cluster bean. Leucaena with maize (Rs 3273 ha⁻¹a⁻¹) and black gram (Rs 3125 ha⁻¹a⁻¹) gave significantly higher net returns over pure crops of Leucaena at wide spacing, maize and black gram. ICRISAT = International Crops Research Institute for the Semi-Arid Tropics- Hyderabad, India. CIAT = Centro International de Agricultura Tropical - Cali - Columbia     

Expected levels of heterozygosity in autotetraploid progeny populations

Summary A breeding program aimed at improving the seed yield in bean for processing was started. Six parents divergent in a range of agronomical characters were crossed according to diallel mating design. Cluster analysis performed on the composite cross population evidenced divergence between F1 hybrids and to maximize genetic recombination, the most different F1 hybrids were intercrossed. A Factor analysis was performed on 7 morphological and yield-determining traits of 15 hybrids F1 and parents. Three Factors, representing patterns of variables interpreted as productivity per plant, growth factor, and branching-productivity, were extracted. These results evidenced the inverse relationship between seed yield components (seeds/pod, pods/plant, and hundred seed weight): i.e. the selection for either variable is detrimental to the other. It may be possible to break this association if the plant construct assures high sink to satisfy all plant requirements: tall and large plants bearing numerous nodes, leaves and reproductive structures. Moreover, the selection practiced simultaneously on the yield components positively affected the seed yield trait. An index of selection and response to selection were estimated on the segregant populations. The realized gain in seed/yield reached after one cycle of selection (C1) was 6.5 g, about 20% over the base population (C0). The expected gain from selection based on the superior 5% plants in C2 families was 25.5% and approached the realized gain. The result of this paper gives evidence to support that the seed yield can be improved by an adequate selection intensity and selection index can be very useful when it is faced with the improvement of several traits at the same time.     

缺磷胁迫下长豇豆幼苗膜脂过氧化及保护酶活性的变化

 研究对缺磷敏感程度不同的长豇豆品种在缺磷胁迫下叶片和根系SOD、CAT、POD活性及MDA含量的变化。结果表明，对缺磷不敏感的‘芦花白’保护酶活性升高或升幅较大，对缺磷敏感的‘二芦白’则活性下降或升幅较小，缺磷胁迫下长豇豆根SOD和POD活性升高。     

光合细菌固定化及其处理黄泔水的研究

以PVA-硼酸混合载体法固定光合细菌处理黄泔水,探讨其对黄泔水处理的较佳工艺条件。结果表明：光合细菌的包埋条件为10％聚乙烯醇、4％SiO2、0．15％海藻酸钠和30％菌液。在好氧黑暗、pH值8．0、菌液接种量20％、装液量100mL条件下,固定化光合细菌处理黄泔水120h,其CODcr去除率为91％。     

普通菜豆籽粒大小与形状的QTL定位

普通菜豆是世界上最重要的食用豆类作物之一,其籽粒大小和形状与产量及外观品质密切相关。本研究以来自安第斯基因库的大粒品种龙270709和来自中美基因库的小粒品种F5910配置杂交组合,获得的F2分离群体分别在哈尔滨大田与北京昌平温室种植,对百粒重、粒长、粒宽、粒厚、长宽比和长厚比6个籽粒性状进行了相关性分析和QTL定位。相关性分析表明,百粒重与粒长、粒宽、粒厚、长宽比、长厚比5个衡量籽粒大小和形状的性状均显著正相关。利用基于完备区间作图方法的Ici Mapping 4.1进行QTL定位,哈尔滨环境下定位到38个与百粒重、粒长、粒宽、粒厚、长宽比、长厚比相关的QTL,表型贡献率介于2.39%~17.37%之间,分布在除第1染色体外的其余10条染色体上;北京昌平环境下定位到21个上述性状的QTL,表型贡献率介于5.92%~22.53%之间,分布在第1、第3、第6、第7、第8、第9和第11染色体上。其中,百粒重QTLSW7与SW7’,SW6.1与SW6’,粒长QTLSL6.1与SL6.1’,粒厚QTLSH11与SH11’在2个环境下的标记区间重叠或者重合,SW7、SW6.1、SL6.1、SW6’和SL6.1’的表型贡献率在10%以上。     

桑黄化型萎缩病植原体核糖体蛋白基因操纵子片段序列的扩增与分析

采用PCR技术对桑树黄化型萎缩病植原体核糖体蛋白基因操纵子的部分基因进行扩增,并对扩增片段进行测序及序列分析。结果表明,利用rpF/rpR引物对扩增得到桑黄化型萎缩病植原体核糖体蛋白基因操纵子片段大小为1240bp（GenBank登录号为GQ373255）,该片段包含rps19 基因部分序列,rpl22 和 rps3 基因的全部序列。相似性分析表明,该片段的核苷酸序列与16SrⅠ-rp亚组中各代表植原体的rp基因核苷酸序列的相似性为96.6-99.9%。构建的进化树表明,桑黄化型萎缩病植原体与报道的桑萎缩病植原体（MD）聚类为一个rp亚组,即rpI-B亚组。     

植原体翠菊黄化组分类研究进展

本文介绍了植原体翠菊黄化组分类研究概况及最新进展,四个遗传进化参数16S rRNA、rp、tuf、secY基因应用于翠菊黄化组植原体的分类,基于16S rRNA、rp、tuf、secY序列的RFLP分析,分别可将翠菊黄化组植原体划分为15个、8个、10个、8个亚组,国际比较菌原体学研究计划署(IRPCM)提出将暂定种‘CandidatusPhytop lasm a asteris’作为翠菊黄化植原体的分类参考标准。     

蚕豆粉渣膳食纤维提取及功能性质研究

以蚕豆渣为原料,通过单因素试验和L9(34)正交试验得出用碱法和酶-碱法提取水不溶性膳食纤维的最佳工艺条件,并测定了2种方法制取的水不溶性膳食纤维的溶胀性和持水性。结果表明,碱法最佳工艺条件为:NaOH溶液浓度6g/100mL,碱浸温度50℃,碱浸时间40min;酶-碱法最佳工艺条件为:NaOH溶液浓度3g/100mL,碱浸温度60℃,碱浸时间50min,胰蛋白酶用量0.4g/100mL。酶-碱法制取的水不溶性膳食纤维具有较好的溶胀性和持水性。     

不同药剂对绿豆轮纹病菌的室内毒力测定

对16种化学药剂和5种生物药剂进行了室内毒力测定,筛选出3种抑制病菌菌丝生长效果 较好的药剂：世高、施保克和多菌灵。世高的有效中浓度最小(EC50=40． 04) ,其抑制菌丝生长的 效果是最好的,其次是多菌灵(EC50=67． 76) ,最后是施保克(EC50=95． 50) 。方差分析结果表 明,3种药剂在不同时间、不同浓度下的抑菌效果明显,5种生物药剂的抑菌效果较差。     

四棱豆的主要农艺性状和品种亲缘关系研究

为了探明四棱豆主要农艺性状的相关性和品种资源的遗传多样性,对11个四棱豆品种的22个主要农艺性状进行了相关性、主成分和系统聚类分析．结果表明：鲜豆荚总产量与主蔓长、主蔓节位数、单株分枝数、豆荚长、单荚重、单株鲜豆荚重有极显著的相关性;四棱豆块根的总产量与单株块根数、单株块根重有显著的相关性．3个主成分对变异的贡献率达86．22％．11个四棱豆品种可以归纳为3大类,蔓生品种和矮生品种的亲缘关系较远．