春小麦新品种酒春8号选育报告

春小麦新品种酒春8号是以自育品系酒0403 F2为母本、宁春4号为父本杂交选育而成的。2014—2015年参加甘肃省春小麦西片水地组区域试验,2 a平均折合产量7 846.65 kg/hm2,较对照品种宁春4号增产6.78%。2016年参加甘肃省春小麦西片水地组生产试验,平均折合产量7 805.1 kg/hm2,较对照品种宁春4号增产7.82%。籽粒含粗蛋白(干基)152.6 g/kg、湿面筋33.1%(以14%水分计),Zeleny沉淀值24.0 mL。适宜在甘肃省酒泉市、张掖市等生态条件类似区域种植。     

春小麦新品种酒春9号选育报告

酒春9号是以巴丰5号为母本,E46-222为父本杂交选育而成的春小麦新品种。2014 — 2015年参加甘肃省西片水地组区域试验,2 a平均折合产量7 817.4 kg/hm2,较对照宁春4号增产6.4％。2016年参加甘肃省(西片)水地组生产试验,平均折合产量7 773.2 kg/hm2,较对照宁春4号增产7.7%。籽粒粗蛋白(干基)含量143 g/kg,湿面筋30.4%(以14%水分计),Zeleny沉淀值24.0 mL。适宜在甘肃酒泉、张掖、武威、白银等生态条件类似区域种植。     

高产稳产春小麦新品种酒春13号选育报告

为全面落实好优质粮食工程,为酒泉市春小麦品种更新换代提供品种支撑。酒泉市农业科学研究院2010年以酒0916F1为母本、永3002为父本进行了有性杂交,对杂交后代通过连续多年的系谱选择,2016年稳定出圃,2017 — 2018年参加水地品鉴、品比试验,选育出了紧凑型春小麦新品种酒春13号。2019 — 2020年参加甘肃省西片(水地组)区域试验,2 a平均折合产量8 031.30 kg/hm2,较对照品种宁春4号增产3.34％。2021年参加甘肃省西片(水地组)多点生产试验,6试点平均折合产量7 342.05 kg/hm2,较对照品种宁春4号增产3.17%。该品种具有高产稳产、优质、农艺性状优良,抗白粉病、抗大气干旱等特点,适宜在甘肃省河西灌区(张掖、武威、酒泉)及沿黄灌区种植。     

节水型春小麦新品种甘春24号选育报告

春小麦新品种甘春24号以张春11号/93-7-31//23416-8-1为母本,以矮败小麦/高加索为父本进行杂交选育而成。2006 — 2007年参加甘肃省西片水地春小麦区域试验, 2 a 14点(次)平均折合产量为7 977.22 kg/hm2,较对照品种宁春4号增产3.68%。2008年参加甘肃省西片水地春小麦生产试验,甘春24号平均折合产量为8 329.50 kg/hm2,较对照品种宁春4号增产12.22％。甘春24号属中晚熟春性普通小麦,生育期89～109 d,株高为78～89 cm,穗长8.4～9.9 cm,穗粒数为33.0～54.2粒,千粒重为40.5～52.2 g。籽粒粗蛋白(干基)含量为15.34％,湿面筋含量31.2％,降落数值340 s, Zeleny沉降值为40.5 mL,吸水率为65.6％,容重805 g/L。面团稳定时间达到8.3 min,面条加工品质为85.5分,色泽评分为8分,馒头加工品质分别85.0分,比容评分为14.0分。中抗条锈,抗旱性中等,丰产、稳产性好,适应性广。经检测,甘春24号为1BL/1RS易位系,且HMW-GS亚基组成为1,7,5+10,具有高产、优质、抗病及抗旱节水等优点。适宜在甘肃沿黄灌区、河西地区及生态相似地区种植。     

春小麦新品种陇春36号选育报告

春小麦新品种陇春36号(原代号陇春13J6)为甘肃省农业科学院小麦研究所从自育春小麦品种陇春23号变异株—顶芒单穗经系统选育而成。2014 — 2015年参加甘肃省春小麦东片水地区域试验,2 a 10点(次)平均折合产量为5 640.75 kg/hm2,较对照品种陇春23号增产8.72%;2016年参加甘肃省春小麦东片水地生产试验,5试点平均折合产量为5 724.00 kg/hm2,较对照品种陇春23号增产4.78%。陇春36号属春性普通小麦,生育期108～115 d,平均株高为94.6 cm,平均穗粒数为31.4粒,平均千粒重为46.1 g,平均容重735.67 g/L。籽粒含粗蛋白163.2 g/kg、湿面筋355.0 g/kg,沉降值35 mL。抗条锈病、白粉病,抗旱性强,丰产、稳产性好,适应性广,品质优,抗倒性强。适宜在甘肃省中部的临夏、兰州、定西生态条件相似的地区和高寒阴湿区及沿黄灌区等地种植。     

高产抗条锈冬小麦新品种天选79号选育报告

为选育适宜甘肃陇南麦区及同类地区推广种植的抗病、丰产且适应性广的冬小麦品种,天水市农业科学研究所以自育高代品系00127-2-2-3作母本、周麦22号作父本配制杂交组合,经多年多点连续鉴定选择,培育成了抗条锈高产冬小麦新品种天选79号。2019 — 2021年参加甘肃省陇南片川区组区域试验,2 a 10点(次)平均折合产量7 437.90 kg/hm2,较对照品种兰天33号增产6.87％。2021 — 2022年度参加生产试验,5点(次)平均折合产量6 910.35 kg/hm2,较对照品种兰天33号增产3.25%。该品种株高78.4 cm,穗长8.0 cm,每穗粒数40.96 粒,籽粒白色,硬质,千粒重46.31 g,有效穗数570 万穗/hm2。具有抗条锈、稳产、抗倒伏、籽粒品质优良等特点,适宜在甘肃省天水渭河川道区及陇南麦区低海拔区种植。     

春小麦新品种陇春35号选育报告

春小麦新品种陇春35号是以9064为母本、陇春8139为父本通过杂交,采用系谱法选育而成。 2014 — 2015 年参加甘肃省旱地春小麦区域试验,2 a 10点(次)平均折合产量为 3 423.15 kg/hm2,较对照品种西旱2号增产12.06%。2016年参加甘肃省旱地春小麦生产试验,5试点平均折合产量为3 964.35 kg/hm2,较对照品种西旱2号增产8.93%。陇春35号属春性中早熟普通小麦,生育期99 d,平均株高98 cm,平均穗粒数31.35粒,平均千粒重47.9 g,容重753 g/L。穗型纺锤形,红粒角质。籽粒含粗蛋白(干基)156.0 g/kg、湿面筋340 g/kg,沉降值29.8 mL。抗病性强,抗旱、耐瘠薄,落黄好。适宜在甘肃省干旱半干旱区的定西市、白银市、兰州市、古浪县等地及生态条件类似地区种植。     

大豆新品种陇豆3号选育报告

为改良大豆种质,提高其产量和品质,甘肃省农业科学院作物研究所以广适、丰产、抗逆性强的品种中品661为母本、吉育88为父本,经人工有性杂交采用系谱法选育出了大豆新品种陇豆3号。2019 — 2020年参加甘肃省大豆区域试验,2 a平均折合产量 2 771.25 kg/hm2,较对照品种陇豆2号增产8.00%。2021年参加甘肃省大豆生产试验,平均折合产量 2 677.20 kg/hm2,较对照品种陇豆2号增产 9.94%。该品种丰产性好,抗花叶病毒病,抗灰斑病,籽粒粗蛋白含量 381.8 g/kg,粗脂肪含量 208.2 g/kg。适宜甘肃省陇东、天水、沿黄和河西灌区春播,陇南地区夏播。     

大豆新品种陇黄2号选育报告

陇黄2号是由甘肃省农业科学院旱地农业研究所和农业生物技术国家重点实验室(香港中文大学)于2008年从山西省农业科学院经济作物研究所引进的以晋豆23为母本、鲁豆4号为父本常规杂交的F3代群体中,采用系谱法选育而成的大豆新品种。2013 — 2014年参加甘肃省大豆品种(系)区域试验,2 a 10点(次)平均折合产量为2 572.28 kg/hm2,比对照品种陇豆2号平均增产9.17%。2015 年参加甘肃省大豆品种(系)生产试验,平均折合产量2 501.70 kg/hm2,比对照品种陇豆2号增产6.09%。陇黄2号田间表现高抗花叶病毒病和大豆黑斑病。籽粒含粗蛋白(干基)385.3 g/kg、粗脂肪(干基)204.2 g/kg,品质优良。陇黄2号适用于机械化作业的间套作带状复合种植。该品种适宜在甘肃省河西灌区、中部沿黄灌区、陇东旱塬区及生态条件相近地区种植。     

高产高淀粉粮饲兼用型玉米新品种丰玉3号选育报告

为解决甘肃自育优良玉米新品种较匮乏、外引玉米新品种对甘肃的生态条件较难适应且退化严重的问题，张掖市博丰农业科技有限责任公司采用重离子辐照结合分子标记辅助选择等现代育种方法，以自育自交系BT0521为母本、自育自交系0571为父本杂交选育出了高产高淀粉粮饲兼用型玉米新品种丰玉3号。2012 — 2013年参加甘肃省玉米中晚熟高密组新品种区域试验，2 a 10点(次)平均折合产量15 621.0 kg/hm2，较对照品种增产2.7%。其中2012年平均折合产量16 536.0 kg/hm2，较对照品种郑单958增产5.4%；2013年平均折合产量14 706.0 kg/hm2，较对照品种先玉335增产2.3%。2014年参加甘肃省玉米中晚熟高密组新品种生产试验，平均产量为16 122.0 kg/hm2，比对照品种先玉335增产7.8%。丰玉3号在甘肃省张掖市春播生育期132 d，株高273 cm，穗长21.0 cm，穗粗5.2 cm，出籽率88.8%，千粒重347.7 g。容重734.2 g/L。丰玉3号籽粒(干基)含粗淀粉766.0 g/kg、粗蛋白89.7 g/kg、赖氨酸3.1 g/kg、粗脂肪36.9 g/kg，属高淀粉玉米品种。该品种高抗茎基腐病和瘤黑粉病，抗大斑病，中抗丝黑穗病，感矮花叶病和红叶病。适宜在甘肃、新疆及同类生态区种植。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.