基于“3414”模型冈杂棉0623肥料效应研究

为探究自育棉花品种冈杂棉0623肥料效应,探讨冈杂棉0623的合理的施肥方法,加快冈杂棉0623的推广。根据“3414”肥料试验模型,2水平推荐氮、磷、钾肥施用量分别为300、150、300kg/hm2。各个处理比对照均有增产,其中N2P2K2处理增产幅度最大为45.65%；且各个处理经济效益较对照高,其中N2P2K2经济效益最高为14768.76元/hm2。结合施肥量、产量及经济效益综合分析,在鄂东棉区推广冈杂棉0623施建议肥量：150-200kg/hm2,磷肥施用量90-100kg/hm2,钾肥施用量为150-200kg/hm2。     

氮、磷、钾不同配比对绿豆产量的影响

2014年以同绿1号为供试材料,研究了不同氮、磷、钾肥配比对绿豆产量构成因子以及产量的影响。通过对绿豆"3414"肥料效应试验,建立肥料施用量与产量的回归方程,求出最佳施肥量。结果表明,科学合理的氮、磷、钾肥配比,不仅能满足绿豆生长发育所需要的营养元素,而且能够促使单株生长发育协调。推荐的最佳施肥量为N 56.7kg/hm2、P(P2O5)76.2kg/hm2、K(K2O)53.5kg/hm2,可获1 526.7kg/hm2的子粒产量。     

湘中南地区烟稻轮作条件下烟草作物的施肥效应与肥料效应函数研究

为了建立适合湘中南双季稻地区烟稻轮作制条件下烤烟作物的平衡施肥模型,确定烟草的合理施肥量,运用联合国粮农组织(FAO)“3414”试验方案,稍作修改,通过田间小区试验,探讨湘中南双季稻地区烟稻轮作制条件下烤烟作物施用氮磷钾肥的增产效应及其最佳施肥量,以为烤烟作物的科学施肥提供科学依据和技术支撑。结果表明：烤烟作物的地力贡献较小,无肥区产量仅占氮磷钾平衡施肥处理（处理6）产量的34.6%~39.4%;增产效果居首位的是氮肥,农大,永州,常宁3个试验点分别增产719.6 kg/hm2、1109.7 kg/hm2和441.0 kg/hm2;运用“3414”试验设计方案得到的各试验点的二元二次肥料效应模型拟合均不成功,农大点推荐施肥宜使用一元二次方程模型,据此所得最佳施肥量分别为N 159.8 kg/hm2,P2O5 86.1 kg/hm2,K2O 152.2 kg/hm2;永州点推荐施肥宜使用三元二次方程模型,据此所得最佳施肥量分别为N 175.2 kg/hm2,P2O5 52.1 kg/hm2,K2O 278.3 kg/hm2;常宁点推荐施肥宜使用一元二次方程模型,据此所得最佳施肥量分别为N 178.7 kg/hm2,P2O5 107.8 kg/hm2,K2O 279.2 kg/hm2;综合各函数的最佳施肥量得到湘中南双季稻地区的烟草作物的施肥决策：烤烟作物对氮、磷、钾养分的最佳产量施肥量为N 172.2 kg/hm2,P2O5 93.3 kg/hm2,K2O 300.0 kg/hm2。     

基于“3414”模型的‘冈杂棉0623’肥料效应研究

为探究自育棉花品种‘冈杂棉0623’肥料效应及合理的施肥方法,加快‘冈杂棉0623’的推广。本研究采用"3414"肥料模型进行试验,其中两水平推荐氮、磷、钾肥施用量分别为300、150、300 kg/hm~2。比较棉花产量构成因素发现各施肥处理高于对照,其中N2P2K2处理各性状表现最佳;各个处理产量较对照均有所增加,随着施肥量增加产量有所增加,但是施肥量3水平条件下,产量较2水平有所下降;对各处理经济效益进行比较分析,施肥处理经济效益较对照要高,其中N2P2K2经济效益最高为14768.76元/hm~2。结合施肥量、产量及经济效益综合分析,发现要获得高产,高收益要合理施肥,平衡NPK肥施用量。在鄂东棉区推广‘冈杂棉0623’,建议施肥量为:氮肥施用量150～200 kg/hm~2,磷肥施用量90～100 kg/hm~2,钾肥施用量为150～200 kg/hm~2。     

NPK用量对露地西兰花产量、养分累积及肥料效率的影响

为了探讨露地西兰花的NPK合理施用量,提出科学的施肥配比。在宁夏引黄灌区通过田间试验研究了不同NPK供应水平对露地西兰花产量和地上部NPK吸收累积的影响,并评价了其肥料效率。结果表明：施用N、P肥对西兰花有显著增产作用,而施K处理间无显著差异。相对于N0和P0处理,增施N、P肥可分别提高23.6%~36.2%和7.6%~11.5%的经济产量。适当增施NPK肥能显著提高西兰花的地上部NPK养分累积。西兰花的肥料利用率、农学效率和偏生产力都随施肥量增加而降低。每施用1 kg N、1 kg P2O5、1 kg K2O分别可生产50.9~184.7、89.3~369.1、53.9~220.2 kg西兰花经济产量,其随施肥量增加呈显著降低趋势。西兰花经济产量与施N量(R2=0.886)、施P量(R2=0.906)和施K量(R2=0.794)都呈二次曲线关系。综合考虑蔬菜产量、养分累积和肥料效率,建议宁夏引黄灌区露地西兰花的施肥量分别为N 189.8~200.0 kg/hm2、P2O5 79.8~86.8 kg/hm2和K2O 80.2~112.5 kg/hm2 ,其施肥配比为1:0.42~0.43:0.42~0.56。     

黔花生二号不同密度及氮、磷、钾肥施用量对经济效益的影响

采用四因子五水平正交回归旋转组合设计,研究种植黔花生二号的经济效益与播种密度、施肥量(N、P、K)间的关系,建立了各因素与经济效益指标的优化数学模式,确立了黔花生二号经济效益(大于18000元/hm2)栽培优化组合方案:密度29.298~30.996万株/hm2;N施用量196.275~219.600kg/hm2(尿素426.7~477.4kg/hm2);P2O5施用量121.26~140.22kg/hm2(过磷酸钙673.7~779.0kg/hm2);K2O施用量196.275~219.60kg/hm2(硫酸钾392.55~439.2kg/hm2)。影响黔花生二号经济效益大小因素的顺序是,密度>施氮量>施钾量>施磷量。     

灌溉条件下燕麦氮、磷、钾配方施肥效应分析及与产量回归模型的建立

为探讨灌溉条件下燕麦品种银燕6号氮（N）、磷（P）、钾（K）配方施肥的肥料效应,采用“3414”试验方案,研究N、P、K不同施用配比对燕麦产量和农艺性状的影响,建立了施肥与产量的回归模型,为构建灌溉条件下燕麦施肥指标体系提供科学依据。结果表明,处理N₂P₂K₂籽粒产量（5100.0kg/hm²）、肥料贡献率（34.8%）、产值（20 400.0元/hm²）在14个处理中均最高;增产效应为N>P>K,并且N、P、K肥间存在明显的交互作用;N、P、K单种肥料施用量与籽粒产量呈抛物线关系,根据拟合函数得出,N、P、K最大施用量分别为229.8、80.5、26.4kg/hm²;根据N、P₂O₅和K₂O施用量对籽粒产量的影响,建立了三因素的施肥数学模型,进一步得出,燕麦产量≥4950.0kg/hm²时,氮（N）︰磷（P₂O₅）︰钾（K₂O）施肥比例为1.54︰1︰0.23,N、P₂O₅、K₂O施用量范围分别是148.8~198.3、>112.5和14.3~37.2kg/hm²。该结论对灌溉条件下燕麦生产具有实际指导意义。     

施氮量对两种类型燕麦物质积累和产量的影响

以皮燕麦白燕7号和裸燕麦白燕2号为材料,连续两年各四茬原位氮肥处理,研究了不同施氮量(0、30、60、90和120kg/hm2)对两种类型燕麦物质积累、产量和产量构成的影响.结果表明,第一年第一茬两类燕麦干物质积累、产量等性状在不同氮肥处理间没有显著差异或明显的规律性,即使不施氮处理,燕麦产量并没有降低.从第二茬开始的后三茬中,不施氮和低氮处理的草产量、子粒产量和产量构成因素等明显降低,在低氮肥处理有随施氮量增加而增加的趋势.子粒产量在施氮量90kg/hm2处理达到最高,但高施氮量处理间差异不显著.两种类型燕麦品种表现一致.     

高海拔地区马铃薯磷肥施用效应研究

为了确定贵州高海拔地区马铃薯对磷肥的需求范围,进行了施磷试验.试验设计5个磷肥水平(P2O5),分别为:0 kg/hm2、45 kg/hm2、90 kg/hm2、135 kg/hm2、180 kg/hm2.每个处理N、K肥用量相同,氮肥(N) 225 kg/hm2,钾肥(K2O) 240 kg/hm2.结果表明适量施用磷肥能促进马铃薯的生长,提高马铃薯大中薯率,增加马铃薯产量和经济效益.结论说明在贵州高海拔地区,在试验条件下,磷肥施用量在135 kg/hm2左右时,马铃薯可以达到产量和经济效益最大化.     

风砂干旱区小豆N、P施肥技术研究

对小豆品种“小丰2号”进行N、P肥试验,结果表明:N、P施肥水平不同小豆产量不同,两者之间变化曲线呈抛物线形状,即产量随N、P肥施入量增加而增加,当施纯N90kg/hm2、纯P135kg/hm2时小豆达到产量最高、利润最大,此后产量随N、P肥施入量增加反而降低。N、P肥之间互作极显著,以施纯N90kg/hm2×纯P135kg/hm2产量最高,比N、P单施产量分别提高10.78%和21.98%。从而确定了在风砂干旱生态条件下小豆最佳N、P施肥量为N90kg/hm2、P135kg/hm2。     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

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.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

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.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

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.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.