山农丰抗棉6号种植密度整枝方式对产量的影响试验

山农丰抗 6号是山东农业大学农学院育成的高产、抗病、优质新品种抗虫棉 ,适宜盐碱地、覆膜、直播、春播、麦棉、瓜棉、菜棉套种。肥水、密度、整枝方式是影响该品种产量的主要因素 ,为找出最佳密度及与之相配套的整枝措施 ,2 0 0 1年 ,笔者在老僧堂乡进行了不同种植密度与整枝方式试验。1　材料与方法　　试验地有机质含量 1 2 1% ,速效氮 75mg kg ,速效磷 2 5mg kg ,速效钾 15 0mg kg ,棉花常规种植法 ,留苗密度 36 5 0 0株 hm2 株左右。试验设 6个处理 ,重复 3次 ,随机区组排列 ,小区面积 0 0 0 33hm2 ,等行距种植 ,0 4 2 0日播种。全…     

稀有植物矮杨梅种子繁殖试验

矮杨梅 (MyricananaCheval.)种子繁殖试验表明 :(1)当年收获种子基本无萌发能力 ;(2 )经低温 (4± 1℃ )层积或沙藏处理 8个月种子能萌发 ,前者发芽率低 (2 9.0 %) ,后者高 (6 7.5 %)。 (3) 6 0℃以上热水浸泡处理种子萌发率高 ;(4)种子在自然状态下不耐贮藏 ,经低温层积贮藏 2年的种子发芽率 (35 .4%)明显高于贮藏 3年种子 (8.2 %) ;(5 )矮杨梅是耐荫性植物 ,幼苗在遮荫条件下才能正常生长。     

高效蓄冷材料筛选与保鲜应用试验研究

为了筛选相变温度适宜和保鲜效果好的蓄冷材料,从而挑选出适宜不同蔬菜保鲜的蓄冷材料,选用水、4.8%氯化钠、10%乙酸铵和15%甲酸钠作为蓄冷材料,了解它们的热力学特性和对黄瓜、甜椒、生菜和西兰花4 种蔬菜的保鲜效果。结果表明：水、4.8%氯化钠、10%乙酸铵、15%甲酸钠的相变温度分别为0、-6、-12、-16℃,在-28℃冷冻条件下从液态到固态的相变时间分别约为6、12、11、18 h,在常温密闭条件下从固态到液态的相变时间分别约为15、6.5、6、7.5 h。4.8%氯化钠作为蓄冷材料对黄瓜、甜椒有较好的蓄冷保鲜效果;15%甲酸钠作为蓄冷材料对甜椒、生菜、西兰花有较好的蓄冷保鲜效果。在生产实践中,对于黄瓜、甜椒等喜温性蔬菜可采用4.8%氯化钠进行蓄冷保鲜,对于生菜、西兰花等半耐寒性蔬菜可采用15%甲酸钠进行蓄冷保鲜。     

细说尤伯球(下)

尤伯球的繁殖尤伯球可采用播种和把植株切顶促生子球然后再用嫁接的办法进行繁殖。播种时要注意:1.把握适宜的时间。播种时间以每年春季4～5月和秋季9月为宜。因为这样可以使前期细小的幼苗避开盛夏和严冬的危害,发育更顺利。2.播种介质使用前要严格消毒。3.细心呵护前期幼苗。尤伯球幼苗前期呈半透明状,十分脆弱,要特别注意保护,盆上不能太干,也不能太湿,浇水采用浸水法,注意遮荫,勤观察,适时喷洒一些灭菌药物。4.最好用新鲜种子插种。新采集的种子(采后1～2个     

不同遮荫条件对蛇皮果生长及生理特性的初步研究

蛇皮果是喜阴植物,遮荫处理对蛇皮果幼苗的生长具有重要作用,笔者研究不同遮荫处理对蛇皮果栽培生长的影响。本试验通过采用不遮荫（CK）、25%遮荫（S1）、50%遮荫（S2）、75%遮荫（S3）及椰子叶遮荫（S4）的处理方式对蛇皮果进行遮荫栽培研究。结果表明,不同处理对于蛇皮果的生长发育影响显著（P<0.05）,其中75%遮荫（S3）处理效果很好,其次是50%遮荫（S2）和椰子叶遮荫（S4）处理,遮荫处理对于蛇皮果的生长具有促进作用。遮荫栽培试验为蛇皮果规模化生产提供了重要的参考意义。     

遮荫网透光度对闽楠苗木生长影响的研究

为了解决闽楠苗木在全光照条件下存活率低的问题,采用遮荫40%、60%、70% 3种遮荫处理,以全光照为对照,进行对闽楠苗木保存率、苗高生长与地径生长的影响试验。结果表明：用遮荫网遮荫使保存率提高41~41.7个百分点,用遮光度为60%的遮荫网较适宜闽楠幼苗的生长,而全光照对闽楠苗期生长不利。     

玉米新品种垦玉 706 的选育

甘肃农垦良种有限责任公司以高产、抗病、抗倒为育种目标,2013 年选用自育系 LKF0601 为母本、LKMB-1 为父本进行杂交选择,育成发芽势强、拱土能力强、幼苗长势强、结实性好的中熟玉米新品种垦玉 706。该品种适宜在 4 月下旬地温≥ 10℃以上的东华北中熟春玉米区播种,以直播栽培方式选择中等肥力以上地块,种植密度 4500 株 /667m2 最为适宜。     

藏药铁棒锤种子发芽特性研究

研究了铁棒锤（Aconitum pendulum Busch）种子在光照和黑暗条件下不同温度（10、15、20、25、30℃和23／28℃变温）处理对发芽率、发芽势和发芽指数的影响。结果表明,铁棒锤种子千粒重为1．66g;最大吸胀率为125．0％,达到饱和吸胀需20h;黑暗环境下15℃有利于种子发芽,发芽率达30．3％,16天内平均发芽指数这1．54,但萌发后光照有利于形成健壮的幼苗。上述结果说明,土壤温度稳定通过15℃是铁棒锤的最佳播期,播种后应采用一定的覆盖遮荫措施,出苗后及时解除遮荫以促进根系发育。     

播期对小麦冬前幼苗生长和积温的调控效应

为了研究播期对小麦冬前幼苗生长和积温的调控效应,以‘光明麦1号’为试验材料,设计不同播期试验,旨在探讨播期对春性小麦冬前幼苗生长发育和积温的影响。结果表明,随播期推迟,出苗率下降,且冬前积温降低,显著影响小麦冬前生育进程,植株叶龄减小,分蘖发生数下降,LAI和干物质积累降低。播种至出苗阶段日均温与出苗天数呈指数相关关系,出苗至越冬始期≥0℃积温与此期天数、叶龄、茎蘖数、LAI和干物质积累呈显著线性正相关。本试验条件下,播期每推迟6天左右,播种至出苗日均温下降1.0~2.5℃,≥0℃积温上升5~15℃,播种至出苗所需天数延长2~5天,出苗至分蘖所需天数延长1~10天,出苗至越冬始期的天数缩短6~11天,出苗率下降1.5~3.5个百分点,越冬始期叶龄减少0.4~1.0,茎蘖数、叶面积指数和干物质积累分别下降100~150万/hm²、0.04~0.51和30~200 kg/hm²。实现春性小麦壮苗的冬前≥0℃积温为500~670℃,适宜播期10月23日—11月4日,最适播期是10月27日—10月29日。     

低温对不同虫态烟草甲的影响

利用低温处理方法,对不同虫态烟草甲进行处理。研究结果表明,各虫态烟草甲耐低温的顺序从高到低依次是:幼虫、成虫、卵。-20℃处理,各虫态烟草甲死亡率都为100%;-10℃低温条件下,处理1h以上,烟草甲卵和成虫全部死亡,处理72h以上,烟草甲幼虫全部死亡;5℃处理72h以上,烟草甲卵不再孵化,5℃处理20d不能使烟草甲幼虫和成虫完全致死,但影响幼虫化蛹和成虫产卵。各温度处理中烟草甲幼虫最终羽化率为0,成虫单雌产卵量为0。0℃,5℃卵最高孵化率均为41.67%。对照中幼虫最终羽化率为77%、卵最终孵化率为52%。     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Relation between wheat-rye crossability and seed set of common wheat after pollination with other species in the Hordeae

Summary Cultivars of common wheat (Triticum aestivum L. em. Thell.) of high wheat-rye (Secale cereale L.) crossability set more seed with pollen of other related species than did wheats of low wheat-rye crossability. This was found to be true for pollen parents from the genera Triticum, Aegilops, Secale, Agropyron and Elymus.     

Breeding apomictic bahiagrass (Paspalum notatum Flügge) with improved turf traits

The development of a turf‐type bahiagrass could have a remarkable impact on the billion‐dollar turf industry in the south‐eastern United States. The goals of this study were to (i) select bahiagrass genotypes with improved turf attributes and (ii) determine the reproductive mode and seed fertility of selected genotypes. The population included mutants, wild types, hybrids and standard cultivars evaluated at two locations for two years. Morphological variation was observed and clonal repeatability (H²) ranged from 0.27 to 0.90. Flowering was extremely reduced in some mutants, which also exhibited dark green colour, finer texture and reduced canopy height. Cytoembryological observations revealed that diploids reproduced sexually and tetraploids by obligate or facultative apomixis. Genotypes with superior seed fertility were identified, while others were comparable to the standard cultivars. While mutant plants exhibited great morphological variation, the random mutations did not affect their reproductive mode, validating the use of mutagenesis in apomictic species. The high H² indicated that selection for improved turf attributes could be successfully performed with the advantage of clonal seed propagation.     

Inheritance of fruit colour in a wild Russian red raspberry seedling

Summary A new gene, i, from a self-incompatible wild Russian Rubus idaeus seedling is described. The gene i interacts with the fruit colour gene T, Tii plants having apricot instead of red fruits, and spines, leaves and stems pigmented to varying degrees. A deficit of apricot-fruited seedlings in progenies segregating for i could be explained by linkage between i and the self-incompatibility S locus with a crossover value of approximately 26.7%.Segregations for spine colour in crosses and backcrosses of the Russian seedling with two green-spined (ttII) raspberries selected for their yellow fruit colour, showed that both the latter carried the spine colour intensifier gene P. This suggests that earlier authors were incorrect in attributing the apricot fruit colour developed by some tt plants to a pleiotropic effect of P.     

Flag Leaf Senescence, as Evaluated by Numerical Image Analysis, and its Relationship with Yield under Drought in Durum Wheat

Senescence was evaluated at different stages of the grain‐filling period in eight durum wheat varieties using numerical image analysis (NIA). The varieties were grown under early, severe drought conditions on the high plains of Sétif in Algeria. After flowering, three different irrigation treatments were applied. Treatment effect was small, while a genotypic effect was noted for most of the senescence parameters. Senescence correlated to biomass, while the maximal rate of senescence, V_smax, correlated to thousand‐kernel weight. The potential of the method of numerical image analysis for monitoring flag leaf senescence, detecting genotypic variability and selecting genotypes with delayed senescence is discussed.     

Cowpea (Vigna unguiculata): Genetics,genomics and breeding

Cowpea, Vigna unguiculata (L.), is an important grain legume grown in the tropics where it constitutes a valuable source of protein in the diets of millions of people. Some abiotic and biotic stresses adversely affect its productivity. A review of the genetics, genomics and breeding of cowpea is presented in this article. Cowpea breeding programmes have studied intensively qualitative and quantitative genetics of the crop to better enhance its improvement. A number of initiatives including Tropical Legumes projects have contributed to the development of cowpea genomic resources. Recent progress in the development of consensus genetic map containing 37,372 SNPs mapped to 3,280 bins will strengthen cowpea trait discovery pipeline. Several informative markers associated with quantitative trait loci (QTL) related to desirable attributes of cowpea were generated. Cowpea genetic improvement activities aim at the development of drought tolerant, phosphorus use efficient, bacterial blight and virus resistant lines through exploiting available genetic resources as well as deployment of modern breeding tools that will enhance genetic gain when grown by sub‐Saharan Africa farmers.     

Screening for resistance to take-all in wheat,triticale and wheat-triticale hybrid lines

Summary Fifteen triticale and wheat-triticale hybrid lines were evaluated for resistance to the take-all fungus Gaeumannomyces graminis var. tritici and compared with five wheat and two rye lines in inoculated field and pot trials. The triticale and wheat-triticale hybrid lines varied in rye chromosome number and degree of resistance expressed. One line, Venus with seven pairs of rye chromosomes consistently showed levels of resistance intermediate between wheat and rye. A trend was observed where increasing rye chromosome content led to greater resistance but exceptions showed that variation within triticales could not be ascribed to rye chromosome content alone.     

Insect resistance in potatoes: sources,evolutionary relationships,morphological and chemical defenses,and ecogeographical associations

Summary The past 25 years, 1686 potato accessions, representing 100 species in the genus Solanum L., subgenus Potatoe, section Petota, were evaluated for field resistance to one or more of the following insect pests: green peach aphid, Myzus persicae (Sulzer); potato aphid, Macrosiphum euphorbiae (Thomas); Colorado potato beetle, Leptinotarsa decemlineata (Say); potato flea beetle, Epitrix cucumeris (Harris); and potato leafhopper, Empoasca fabae (Harris). Accessions highly resistant to green peach aphid were identified within 36 species, to potato aphid within 24 species, to Colorado potato beetle within 10 species, to potato flea beetle within 25 species, and to potato leafhopper within 39 species. Resistance levels were characteristic within Solanum species. Insect resistance appears to be a primitive trait in wild potatoes. Susceptibility was most common in the primitive and cultivated Tuberosa. Insect resistance was also characteristic of the most advanced species. The glycoalkaloid tomatine was associated with field resistance to Colorado potato beetle and potato leafhopper. Other glycoalkaloids were not associated with field resistance at the species level. Dense hairs were associated with resistance to green peach aphid, potato flea beetle, and potato leafhopper. Glandular trichomes were associated with field resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Significant correlations between insect score and altitude of original collection were observed in six of thirteen species. Species from hot and arid areas were associated with resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Species from cool or moist areas tended to be resistant to potato aphid.Abbreviations EBN Endosperm Balance Number     

A self-fertile trigeneric hybrid in the Triticeae involving Triticum,Hordeum, and Secale

Summary A self-fertile trigeneric hybrid in the Triticeae involving species from the Hordeum, Triticum and Secale genera has been produced. The trigeneric hybrid was obtained by crossing octoploid triticale (x Triticosecale Wittmack) with octoploid tritordeum (H. chilense × T. aestivum amphiploid). The trigeneric hybrid presented a genome constitution AABBDDRH^ch and 2n=8X=56 chromosomes. The cytogenetical analyses showed no chromosome instability nor homeologous pairing between Hordeum and Secale chromosomes. In the F₂ generation the chromosome number ranged from 42 to 52. Within this range, the plants with smaller numbers of chromosomes were more frequent. A preferential transmission of rye chromosomes could be inferred.     

Evolving gene pools in crop plants

Summary The three gene pool system can be applied usefully to the whole range of crop plants. The primary gene pool (GP1) show varying degrees of fragmentation. No morphological discontinuity is apparent between wild and cultivated Lathyrus sativus but clear discontinuities have developed between conspecific wild and cultivated Phaseolus and Vigna species. Further discontinuities can develop in cultigens where disruptive selection has been practiced, as in Beta vulgaris, Linum usitatissimum and Brassica oleracea where more than one distinct crop has evolved within a single biological species. Each such crop has developed its own distinctive gene pool.