An evaluation on intensity of infection of Pseudocercospora leaf spot disease of cowpea cultivars (Vigna unguiculata L. Walp), with respect to infector rows, dates of inoculation and cultivars, grown under field conditions in Northeast Thailand

This investigation was carried out at the Experimental Farm, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand to evaluate intensity of infection of Pseudocercospora Leaf Spot disease of cowpea cultivars, grown under field conditions with the use of Yasothon soil series (Oxic Paleustults). The experimental design used was a strip split plot design with four replications. The experiment consisted of three factors, i.e., with and without infector rows (Factor A), with and without inoculation and inoculated dates, i.e. none inoculation, inoculated at days 15 and 30 after sowing of seeds in main plots (Factor B) and three cowpea cultivars of KVC7, KKU25 and IT81D-1228-14-1 (Factor C). The results showed that the use of infector rows of cowpea plants (KKU25) being sown at 15 days before sowing seeds of cowpea cultivars in main plots gave a similar intensity of disease as those infector rows being sown at 30 days before sowing seeds of cowpea cultivars in main plots but significantly higher than without infector rows. Pathogenic disease being inoculated to the cowpea plants at 15 days after the sowing of seeds in main plots gave significantly higher intensity of disease than none inoculation. The establishment of infector rows at 15 days ahead of the sowing of seeds in main plots together with an inoculation of the disease at 15 days after the sowing of seeds in main plots gave the best results in evaluating amount of the infected disease. Thus infector rows surrounded the main plots are required whenever trials on disease evaluation are taken place.     

Soil nutrients and liming on dry weight yields and forage quality of Signal grass (Brachiaria decumbens Stapf.), grown on Korat soil series (oxic paleustults) in northeast Thailand

This experiment was carried out at Khon Kaen University Experimental Farm, Khon Kaen University, Thailand during the 2004-2005 aiming to investigate effect of phosphorus (P) and dolomite levels on dry weight yields (DWYs) and forage quality of Signal grass. A 4x3 factorial arranged in a Randomized Complete Block Design (RCBD) was used. Four P levels were: 0, 100, 200 and 400 kg P2O5 ha-1 and three dolomite levels were: 0, 625 and 2,500 kg ha-1. The Signal grass plants were grown on Korat soil series, (Oxic Paleustults). A quadrat with a dimension of 50x50 cm was used for grass yield harvests. Crude Protein (CP), Acid Detergent Fibre (ADF), Neutral Detergent Fibre (NDF) and Dry Matter Degradability (DMD) contents were determined. Tissues phosphorus and calcium contents were also analysed. The results showed that an increase in dolomite levels increased soil pH from 4.4 to 5.1 for levels 1 and 3, respectively. An increase in P levels increased available soil P from 4.56 to 28.38 ppm for levels 1 and 4, respectively. For the first year experiment, dolomite levels had no significant effect on DWYs, whilst P levels significantly increased but only up to level 2. The 2-year average DWYs reached 11,368 kg ha-1 for level 4 of P. With the first year rainy season harvests, P levels had its significant effect on ADF and DMD up to level 2 but not with CP and NDF. For the dry season harvests, P and dolomite levels had no significant effects on forage quality. Dolomite levels had no significant effect on P and Ca contents of the Signal grass tissues but an increase in P levels increased P contents. P and Ca contents, in most cases, were higher for the dry season than the rainy season.     

An identification in fish of the genus Puntius Hamilton 1822 (Cypriniformes: Cyprinidae) of some wetlands in northeast Thailand with the use of random amplified polymorphic DNA technique

The experiment was carried out during the 2003 to 2006 at the Department of Fisheries, Khon Kaen University, Khon Kaen, Thailand in collaboration with the Department of Biosciences, the University of Hertfordshire, College Land, Hatfield, Herts, UK. Molecular RAPD technique was used for the determinations of DNA patterns of the fish genus Puntius Hamilton 1822. The fish samples of 1,500 individual fish were collected from fifteen wetlands in Northeast Thailand and they were used for DNA extraction. Before the experiment was carried out the fish samples were morphologically identified and it was found that the collected fish consisted of 9 species i.e., Puntius altus, P. aurotaeniatus, P. binotatus, P. gonionotus, (e) P. leiacanthus, P. orphoides, P. partipentazona, P. schwanenfeldi and P. wetmorei. Genomic DNAs were extracted from 5 mg of muscle tissues (skeleton muscles) with the use of PUREGENE DNA Isolation Kit for Laboratory Use, Gentra Systems, USA. Eighty decamer primers from four kits were subjected to a preliminary test. It was found that only 10 decamer primers were most suited for this PCR amplification. The results showed that genetic distant values being established among and between pairs of the fishes of the 9 fish species ranged from 0.191 to 0.456 for a pair between Puntius gonionotus and Puntius altus and a pair between Puntius schwanenfeldi and Puntius leiacanthus, respectively. Similarity coefficient values within the 9 fish species ranged from 0.109 to 0.231. The results on a Dendrogram of clusters showed that there were 5 minor groups of the 9 fish species but the 9 species could not be split or shifted into other genera of the fish due to small differences found within the values of similarity coefficients.     

An analysis on flavonoids contents in Mao Luang fruits of fifteen cultivars (Antidesma bunius), grown in northeast Thailand

This investigation was carried out at the Department of Biotechnology, Faculty of Technology, Mahasarakham University, Mahasarakham Province, Northeast Thailand. The study aimed to analyze flavonoids contents in ripe fruits of fifteen Mao Luang cultivars (Antidesma bunius) harvested from dipterocarp forest of the mountainous areas of Phupan Valley, Sakon Nakhon Province, Northeast Thailand. The experiment was laid in a Completely Randomised Design (CRD) with five replications. The fifteen cultivars were used as treatments. An amount of 2 kg of ripe fruits of each cultivar was collected and extracted for juice solutions. The analysis was carried out with the use of RP-HPLC laboratory system. The results showed that fruits of the fifteen Mao Luang cultivars contained three different kinds of flavonoids, i.e., catechin, procyanidin B1 and procyanidin B2. These three chemical compounds were the major flavonoids in all analyzed fruit samples of the fifteen cultivars. The highest amount of procyanidin B1 was found with Lompat followed by Maeloogdog with values of 4122.75 and 3993.88 mg 100 g(-1) of fresh weight, respectively and the highest amount of procyanidin B2 was found with Sangkrow 2 followed by Fapratan with values of 5,006.39 and 3,689.42 mg 100 g(-1) of fresh weight, respectively. Catechin contents in fruits of the fifteen cultivars varied from 73.39 to 316.22 mg 100 g(-1) of fresh weight for Sangkrow 5 and Fapratan, respectively where Fapratan was the highest among the fifteen cultivars followed by Sangkrow 2 with values of 316.22 and 175.40 mg 100 g(-1) of fresh weight, respectively. In terms of grand total amounts of flavonoids, Sangkrow 2 was the best followed by Fapratan, Sangkrow 1 and Maeloogdog, whilst the rest were of secondary importance.     

水稻不同类型亲本杂种F2产量性状表现及遗传参数分析

通过对盐粳68/密阳50、盐粳68/盐粳34、盐粳68/一目惚3个不同类型水稻杂交组合F2群体产量性状表现及遗传参数估算,分析了水稻不同类型亲本杂种后代与亲本的关系。结果表明,产量性状的表现及其遗传参数因亲本类型的不同而有明显差异。籼、粳亚种间杂交组合F2群体产量性状变异幅度大、遗传力较高、遗传进度也较大,因而有广泛的选择潜力。     

杂交小麦杂种一代白粉病抗性表现规律的研究

为探讨杂交小麦杂种一代白粉病的抗性表现规律,以陕西不同地区小麦白粉病流行菌种做菌源,通过田间和苗期接种,对9份抗、感白粉病小麦亲本材料和9份大田感病品种及其杂交F1代进行抗病性鉴定,并结合SCAR和SSR分子标记进行了检测.结果表明:(1)以N95175、N9209为亲本的杂交F1含有Pm21基因,苗期和成株期抗病性均很好,与抗病亲本的抗病性表现基本一致,符合显性遗传,其抗病性主要由显性单基因控制.(2)以N9134、N9227A为亲本的杂交F1含有PmAS846基因,成株期抗病性较好,苗期大部分表现抗病;以N9227A为亲本的杂交F1中有40%的杂交组合表现中感,该抗性基因不完全符合单基因显性遗传,其表达在一定程度上受遗传背景及环境的影响.(3)中国春为苗期感病、成株期抗病材料,其与抗病亲本杂交F1代的抗病性接近或略高于抗病亲本;与感病品种杂交F1代的抗病性介于双亲之间.(4)白粉病遗传属于细胞核遗传,正反交F1代苗期抗病性无明显差异,杂交种的抗病性与双亲相关.因此, 在组配小麦强优势杂种组合时应尽量选用抗病的品种作为亲本之一,并考虑慢病性品种的应用.     

大豆高蛋白育种的亲本选配和后代选择的研究——Ⅰ大豆杂交F_2、F_3、F_4代蛋白质含量的遗传变异特点

用蛋白质含量不同的九个亲本配成六个组合,对其F_2、F_3、F_4代蛋白质含量的遗传基因作用方式和遗传参数等进行了系统的研究。试验结果表明,除C_2外,其它五个组合的蛋白质含量遗传主要是基因的加性效应,可用中亲值预测杂交后代蛋白质含量的平均表现。组合C_2除基因的加性效应外,还存在显性效应。多数组合蛋白质含量的遗传力一般中等偏高且随着世代的升高而增加。不同组合F_2、F_3、F_4代蛋白质含量变异系数和遗传进度较大,以及高蛋白超亲个体的普遍存在,均表明了早期世代选择高蛋白个体的必要性和可能性。     

太湖流域粳稻地方品种产量相关性状的遗传分析

采用主基因+多基因混合遗传模型,对亲本穗部性状差异较大的3个杂交组合,大头稻/呆长青（组合Ⅰ）、老来红/盐粳2号（组合Ⅱ）和呆长青/上海青（组合Ⅲ）的后裔世代的产量相关性状进行了遗传分离分析,得到了这些性状的最适遗传模型。结果表明：组合Ⅰ每穗总粒数的最适遗传模型为一对主基因+加性 显性多基因混合模型,而组合Ⅱ、Ⅲ为一对完全显性主基因+加性 显性多基因遗传模型;组合Ⅱ、Ⅲ的单株有效穗数受一对主基因控制,组合Ⅰ则受两对主基因控制;组合Ⅰ、Ⅱ千粒重的遗传模型为两对主基因+多基因模型,组合Ⅲ为一对主基因+多基因遗传模型;每穗实粒数为两对主基因遗传模型。选用P1、P2、F1、B1、B2、F2六世代联合分离分析方法,相比于单个分离世代的分析方法,增加了试验的精确度,保证了分析结果的准确性,并可鉴别多基因的存在。根据试验结果,分析了不同性状、不同组合的育种策略。     

Mapping a Rice Glabrous Gene Using Simple Sequence Repeat Markers

Inheritance analysis and gene mapping of the glabrous trait were conducted using the crosses between a pubescent rice material Chuanxiang 29B (an aromatic elite maintainer line of hybrid rice), and two glabrous rice materials, Lemont and R2 (R2 is a new restorer line of hybrid rice). All F1 plants from the two crosses had pubescent leaves, confirming that the pubescence trait in Chuanxiang 29B is dominant over the glabrous trait. In F2 individuals, the segregation ratio of three pubescent to one glabrous plant suggests that a single glabrous gene was present in Lemont and R2. Using the bulked segregant analysis, the linkage analysis of the simple sequence repeat markers showed that the glabrous gene, gl-1, was flanked by GL311 and GL8 with the genetic distances of 0.19 and 0.92 cM on chromosome 5, respectively.     

陕北黄芥黄色种皮的遗传研究

本研究采用黄芥（Brassica juncea L.）与两个不同来源的褐籽类型芥菜型油菜杂交，研究黄芥黄色种皮的遗传。结果表明：黄芥的粒色主要受母体基因型控制，褐色对黄色为显性；F2和BC1世代株间乃至株内颜色不尽一致，但黄色单株和褐色单株能够明显区分，褐色和黄色的比例分别符合3:1和1:1的分离比例，证明黄芥的粒色主要受一对主效基因控制，同时受修饰基因和环境的影响。黄籽和褐籽杂交F2代粒色与几个品质性状的相关分析，结果证明除含油量与粒色密切相关外，其脂肪酸组分的平均值与种皮颜色也有一定的相关性。     

合系4号5个低直链淀粉突变体的遗传分析

 对粳稻品种合系4号诱变产生的5个低直链淀粉突变体YM1、YM2、P152、P153、P154进行了遗传分析。这5个低直链淀粉突变体的低直链淀粉含量均受一对隐性基因控制,并具等位性,且与wx位点不等位。直链淀粉含量较高的YM1（10.50%)与其他4个低直链淀粉含量突变体杂交F2存在着由一对等位基因控制的分离现象,直链淀粉含量较高对较低表现为显性。     

Rooting traits of peanut genotypes with different yield responses to pre-flowering drought stress

Water stress during the vegetative development normally is not detrimental and sometimes actually increases yield of peanut (Arachis hypogaea L.). Root growth might play an important role in response to early season drought in peanut and might result in an increase in yield. Information on the response of root characters of diverse peanut genotypes to these conditions will provide useful information for explaining mechanisms and improving peanut genotypes for exploiting positive interaction for pod yield under pre-flowering drought. The aim of this study, therefore, was to investigate the root dry weight and root length density of peanut genotypes with different yield responses to pre-flowering drought stress and their relationships with pod yield. Field experiments were conducted at the Field Crop Research Station of Khon Kaen University, Khon Kaen, Thailand during February to July 2007 and during February to July 2009. A split-plot experiment in a randomized complete block design was used. Two water management treatments were assigned as the main plots, i.e. field capacity and pre-flowering stress, and six peanut genotypes as the sub-plots. Total crop dry matter, root dry weight and root length density were recorded at 25 DAE, R5 and R7. Top dry weight and pod yield were measured at harvest and pod harvest index (PHI) was computed using the data on pod yield and biomass. Peanut genotypes were categorized into three groups based on their responses to drought for pod yield, e.g. increasing, decreasing and non-responsive groups. The genotypes of each group showed a differential response for root quantity and distribution. The increasing pod yield group had more root dry weight and root length density in the deeper soil layers during pre-flowering stress compared to the non-stress treatment. The non-responsive group showed no root response under pre-flowering drought conditions compared to the non-stress treatment. A larger root system alone without considering distribution may not contribute much to pod yield but a higher RLD at deeper layers may allow plants to mine more available water in the sub-soil. However, as yield is a complex trait, several mechanisms may be involved. The increasing pod yield group also had the ability to maintain a high PHI.     

Genetic Analysis and Mapping of Dominant Minute Grain Gene Mi3（t） in Rice

Grain size, determined chiefly by grain length, is one of the main factors affecting the grain yield in rice production. To study the trait of rice grain size, F1 and F2 populations were developed from crosses Shuhui 881/Y34 and Shuhui 527/Y34, and genetic analysis for minute grain was performed. The F1 populations showed minute grains, and grain size segregations in the two F2 populations were both in accordance with the ratio of 3：1, indicating that minute grain in Y34 was controlled by a completely dominant gene. By using the F2 population from Shuhui 881/Y34, this dominant gene, tentatively designated as Mi3（t）, was mapped based on SSR markers in the interval between RM282 （genetic distance of 5.1 cM） and RM6283 （genetic distance of 0.9 cM） on the short arm of chromosome 3.     

An analysis on organic acids contents in ripe fruits of fifteen Mao Luang (Antidesma bunius) cultivars, harvested from dipterocarp forest of Phupan Valley in northeast Thailand

This experiment was carried out in the rainy season (May-October) of the 2006 at the Department of Biotechnology, Faculty of Technology, Mahasarakham University, Mahasarakham 44000, Thailand to analyse organic acids contents in ripe fruits of fifteen Mao Luang cultivars harvested from dipterocarp forest, Phupan Valley, Sakon Nakhon, Northeast Thailand. The experiment was laid in a Completely Randomised Design (CRD) with four replications. The fifteen Mao Luang cultivars were used as treatments. The results showed that there were two groups of organic acids contents in ripe fruits of Mao Luang cultivars i.e., major and minor. The major group of organic acids includes: tartaric acid (7.97-12.16 mg g(-1) of fresh weight), ascorbic acid (10.01-16.55 mg g(-1) of fresh weight), citric acid (4.44-11.73 mg g(-1) of fresh weight) and benzoic acid (8.13-17.43 mg g(-1) of fresh weight) and the minor group includes malic acid (3.05-4.52 mg g(-1) of fresh weight), lactic acid (1.12-4.09 mg g(-1) of fresh weight), oxalic acid (1.00-1.45 mg g(-1) of fresh weight) and acetic acid (0.19-0.69 mg g(-1) of fresh weight). Khumlhai cultivar gave the highest amount of ascorbic acid followed by Lompat, Phuchong, Sangkrow 2 and Maelookdog cultivars. Sangkrow 2 and Phuchong cultivars gave the highest ratio between tartaric and malic acids. Total soluble solid content (TSS%) was highest with Sangkrow 5 cultivar, whilst Total Organic Acids (TOA) was highest with Phuchong cultivar and ratio between TSS:TOA was highest with Sangkrow 2 cultivar. Juice % was highest with both Sangkrow 2 and 3 cultivars, whilst Fapratan and Lompat cultivars ranked the second.     

大豆种间杂交主要农艺性状和蛋白质含量的遗传变异研究

本文对大豆种间杂交(Glycine max (L) Merril×G. soja Sieb. and Zucc., G. max×G.gracilis Skvok Tzow)后代的性状表现及基因效应进行了研究,并初步分析了以栽培大豆为轮回亲本的回交效应。结果表明:F_1代育性不完全正常。上位性基因效应是普遍存在的、不可忽视的重要遗传组成成分。种间杂交后代分离广泛,类型丰富。利用野生资源成败的关键在于亲本选配。回交是利用野生资源的一条有效途径。半野生大豆的价值不容忽视。     

中国橡胶树棒孢霉落叶病疫情调查及其发生规律初探

2011~2013年,项目组对云南、海南、广东和广西等橡胶主产区的棒孢霉落叶病（CLFD）疫情进行调查并对其发生规律进行了初步分析。结果发现：总共调查的81个监测点中,约有92％的监测点发现了该病的为害,且疫情逐年加重,以海南省的大丰农场、西庆苗圃、十月田苗圃和保显农场,云南省的勐醒农场、蚂蝗堡农场和坝撒农场以及广东省的红十月农场等监测点的发病率最高,病情严重。主栽品种田间调查发现,文昌11、云研277-5、云研77-4和热研7-33-97等品种的抗/耐性水平较高,而RRIM600、PR107、GT1和红星1等品种的抗/耐病性水平较差。全年病害消长动态调查发现,该病一般3~4月出现病情,8~9月病情急剧上升,10~11月达到全年最高峰,后逐步下降。多年的调查结果发现,棒孢霉落叶病的发病率和病情指数呈逐年加重趋势,且主栽品种中很少有品种（品系）表现出耐病或抗病性。     

云南地方品种子预44中一个新的抗稻瘟病基因的定位

【目的】子预44是具有广谱持久稻瘟病抗性的云南地方粳稻品种。为了揭示子预44广谱持久抗瘟机制并在抗稻瘟病育种中进行有效利用,【方法】利用江南香糯与子预44杂交构建的遗传群体及分离自云南罗平的稻瘟病菌株LP36进行子预44的抗性遗传分析和抗性基因定位。【结果】子预44对LP36的抗性为单显性基因控制,暂定名为Pi-zy4(t),它位于水稻第4染色体长臂上SSR标记RM5503与RM3276之间约318 kb区间内。【结论】Pi-zy4(t)为新的抗稻瘟病基因。研究结果为子预44的育种利用和Pi-zy4(t)基因的克隆提供了重要信息。     

Foliar reaction toPhytophthora infestans in inoculated potato field trials in Michigan

Late blight, caused byPhytophthora infestans, is the most important disease of potato worldwide and foliar resistance is an important component of managing late blight in the field. The objective of this research was to identify germplasm for use in breeding cultivars with foliar resistance toP. infestans. More than 500 clones were tested from 1997 to 2002 in inoculated (US8 genotype) field experiments conducted at the Michigan State University Muck Soils Research Farm in Bath, Michigan. All of the current commercial cultivars tested were classified as susceptible toP. infestans. The most resistant clones were A90586-11, AWN86514-2, B0718-3, Jacqueline Lee (MSG274-3), MSI152-A, MSJ307-2, MSJ317-1, MSJ453-4Y, MSJ456-2, MSJ456-4, MSJ461-1, MSK101-2, MSK128-1, NY121, LBR8, LBR9, Tollocan, and Torridon. Some of these resistant selections were from crosses with B0718-3, Jacqueline Lee, and Tollocan suggesting that the resistance toP. infestans was transmissible. These resistant clones will provide the opportunity to breed late-blight-resistant cultivars from a diverse pool of cultivated germplasm. Consistent foliar reaction toP. infestans over years suggested that the Michigan State University Muck Soils Research Farm is a valuable location for North American breeders to assess the reaction of potato germplasm to the US8 genotype of late blight.     

微胚乳超高油玉米子粒含油率的主基因+多基因遗传分析

微胚乳超高油玉米是一种专用型油料玉米,具有很好的应用前景。选择两个微胚乳超高油玉米组合,通过P1、F1、P2、B1、B2和F2 六世代联合分析法,研究分析其子粒含油率的遗传规律。结果表明,2个组合子粒含油率的遗传均符合2对主基因+多基因遗传模型。组合Ⅰ主基因遗传率在B1、B2和F2分别为69.00%、35.03%和68.99%,多基因遗传率分别为14.91%、46.97%和17.70%。组合Ⅱ 主基因遗传率在B1、B2和F2分别为46.80%,42.92%和48.25%,多基因遗传率分别为29.41%、34.76%和35.91%。     

Association between aflatoxin contamination and drought tolerance traits in peanut

The current study investigates the association between drought tolerance traits and aflatoxin contamination in peanut grown under long-term drought. Two field experiments were conducted at Khon Kaen University, Thailand using a split–split plot design with three drought stress levels as main plots, 11 genotypes as sub-plots, and two soil inoculations of Aspergillus flavus treatments as sub-sub-plots. The effects of temperature, soil moisture and A. flavus population on kernel colonization and aflatoxin contamination, and drought tolerance traits viz. specific leaf area (SLA) and root length density (RLD) were measured. The results demonstrated that elevated soil temperatures and reduced soil moisture, favored aflatoxin production. Drought in combination with higher levels of A. flavus inoculum load in the soil resulted in an increase in the fungal populations in the soil which in turn resulted in increased kernel colonization and subsequent aflatoxin contamination. A combination of SLA and RLD, and kernel colonization had a significant influence on aflatoxin contamination under drought conditions in both seasons (r = 0.73** and 0.76**). The results revealed that drought tolerance traits (SLA and RLD) could be contributing to resistance to aflatoxin contamination suggesting that a combination of SLA, RLD and kernel colonization could be used as selection criteria in selecting parents for aflatoxin resistance.