Genotypic response of faba bean to water stress

Forty resistant rice cultivars were studied for theinheritance of resistance to bacterial blight usingPhilippine races of Xanthomonas oryzae pv.oryzae (Xoo). Results showed that all thevarieties have at least two recessive genes forresistance. One of these genes governs resistance torace 1 (PXO61) while the other gene confers resistanceto race 6 (PXO99). In addition to the recessivegenes, nine of the varieties possess another dominantgene which also confers resistance to race 1.Allelism tests revealed that the recessive genesgoverning resistance to race 1 in 39 varieties areallelic to xa5 while the dominant genes in thenine varieties are allelic to Xa4. Therecessive gene conferring resistance to race 1 incultivar Sada Diga is inherited independently of xa5. Similarly, the recessive genes governingresistance to race 6 in all the varieties arenon-allelic to xa13. The allelic relationshipsof these genes with xa-24(t), a new recessivegene identified in cultivar DV86 which conveysresistance to race 6 are now being investigated.     

四川小麦主要生产品种（系）分小种抗条锈性鉴定

１９９５年，用优势条锈小种条中２９号，条中３０，３１号及混合菌种对我省６０个小麦生产品种，进行分小种成株期锈性鉴定。结果表明，我省绝大多数小麦品种抗条中２９号及其以前菌系；感条中３０和３１号新菌系。     

Host-status and host-sensitivity of wild Cucumis species to Meloidogyne incognita race 4

Abstract

Wild watermelon (Cucumis africanus) and wild cucumber (Cucumis myriocarpus), which are highly resistant to the southern root-knot nematode (Meloidogyne incognita) race 2, have the potential for serving as seedling rootstocks for the highly nematode-susceptible watermelon (Citrullus lanatus) cultivars. In South Africa, due to high labour costs, most cotton farmers are turning to watermelon production. In these regions, there is high incidence of M. incognita race 4. A pot experiment in the greenhouse was, therefore, initiated to investigate the host-status and host-sensitivity of Cucumis africanus and Cucumis myriocarpus to M. incognita race 4, when inoculated with 0, 200, 600, 100, 1400, 1800 and 2200 eggs and second-stage juveniles (J2s). At harvest, 56 days after inoculation, the reproductive factor values at all levels of inoculation were less than one. Penetration indices on both plant species were greater than one, suggesting that the resistance was post-infectional and therefore, introgressible. Sex (male: female) ratios of M. incognita race 4 on the two Cucumis species were greater than one, suggesting that more J2s were converted into males. Infection of Cucumis species by the test nematode had no effect on yield components of the two plant species due to poor feeding sites. The two Cucumis species were, therefore, resistant to M. incognita race 4, with post-infectional resistance, where the sex ratio was skewed towards maleness. Thus, the two Cucumis species have the potential to be used as nematode-resistant rootstocks in watermelon production.     

Effect of annealing from traditional nixtamalisation process on the microstructural,thermal, and rheological properties of starch and quality of pozole

Eleven maize landraces were evaluated for pozole quality. The microstructural, thermal and rheological properties of annealed starch granules determine most of the quality of pozole. Annealed starch in traditional nixtamalisation has an important role in increasing gelatinisation onset (To), peak (Tp) and final (Tf) temperatures; peak, setback and final viscosity as well as the stability of the starch granule, all of which significantly affect pozole quality. Annealed starch in Cacahuacintle nixtamal (pozole end-use) increased temperatures To, Tp and Tf by >5.2, >3.8 and >4.1 °C respectively, and narrowed the range Tf − To from 13.78 to 12.62 °C. The enthalpy was reduced from 6.76 to 5.85 J/g, while the nixtamal starch in tortilla maize landraces presented fewer annealing effects. The annealing effect in nixtamal starch seems to stabilize the starch granules and avoid their collapse, compared to native starch, as shown by the X-ray diffraction peak intensity and pattern that is similar to unprocessed maize. Starch in nixtamal changes from Type A to Type V pattern in pozole. Kernel physical parameters, although important, affected the quality to a lesser extent, with the exception of the flotation index. Cacahuacintle maize landrace showed the best quality and yield as well as a short pozole cooking time.     

Morphological and molecular characterization of melon accessions resistant to Fusarium wilts

Fusarium wilt incited by Fusarium oxysporum f. sp. melonis (F.o.m) is one of the most widespread and devastating melon diseases. While resistance to physiological races 0, 1, and 2 is relatively frequent in different botanical varieties, sources of resistance to race 1,2 are restricted to a few Far-Eastern accessions. In this work, the results of a screening for resistance to F.o.m. race 1,2 among 32 accessions are presented. Three Japanese accessions (‘Kogane Nashi Makuwa’, ‘C-211’, and ‘C-40’) showed the highest resistance levels, but useful levels of resistance were also detected in one Russian ‘C-160’ and two Spanish (‘C-300’ and ‘Mollerusa-7’) accessions. These resistant materials, together with other accessions previously described as resistant to F.o.m. races 0, 1, and/or 2 have been morphologically and molecularly characterized. Based on cluster analysis, these accessions have been grouped according to the botanical subspecies they belong to. Assessment of genetic diversity indicated that the resistant accessions to races 0, 1 and 2, are scattered along the established clusters. On the other hand, high levels of resistance to the race 1,2 could be found only among accessions belonging to Cucumis melo subsp. agrestis, nevertheless, a certain degree of resistance to this race could also be found within some accessions belonging to subsp. melo. As far as we know, this is the first report of resistance to F.o.m race 1,2 found out from the Far-Eastern melon material. Based on fruits characteristics, it appears that several inodurus and cantalupensis accessions could be exploited in breeding programs as resistance sources to F.o.m races 0, 1 and/or 2 for the improvement of these melon types. The accessions with the highest levels of resistance to the race 1,2 appeared to be very distant both molecularly and morphologically from the commercial types. Nevertheless ‘C-160’, ‘C-300’, and ‘Mollerusa-7’ classified as var. inodorus are morphologically very similar to the Spanish commercial types and might be used as resistant sources in breeding these melon types.     

云南咖啡锈菌小种鉴定

为明确云南咖啡锈菌小种类型,采用国际通用的 19 个咖啡锈菌生理小种鉴定寄主,利用人工接种鉴定的方法,对采自云南咖啡主产区 12 县（市）的 51 份咖啡锈菌进行鉴定,鉴定出 9 个小种,分别为 VIII（v2,3,5）、XXXIII（v5,7 or v5,7,9）、XXXIV（v2,5,7 or v2,5,7,9）、XXXVII（v2,5,6,7,9）、XLI（v2,5,8）、XLII（v2,5,7,8 or v2,5,7,8,9）、New race（v2,5,6,7）、New race（v1,2,5,7 or v1,2,5,7,9）、New race（v1,5,7 or v1,5,7,9）,这 9 个小种均为国内首次鉴定,其中小种 XXXIII、XXXIV、New race（v2,5,6,7）、New race（v1,5,7 or v1,5,7,9）、New race（v1,2,5,7 or v1,2,5,7,9）、XLI 和 XLII 均侵染 Catimor7963,小种 XXXVII 侵染 CatimorT5175。     

Characterizing races of Meloidogyne incognita, M. javanica and M. arenaria in the West Mediterranean region of Turkey

A total of 95 samples of Meloidogyne incognita (60), Meloidogyne javanica (28) and Meloidogyne arenaria (7) collected from West Mediterranean region of Turkey were tested for identifying races of the nematodes using the North Carolina Differential Host Test. Races 2 and 6 of M. incognita were identified in 58 and 2 samples, respectively. Race 1 of M. javanica was identified from all 28 samples. Races 2 and 3 of M. arenaria were identified in 5 and 2 samples, respectively. The results also showed that two races of M. incognita and all races of M. javanica did not attack on pepper cv. California Wonder. These findings may contribute to improving resistant varieties and may also provide basis for developing a cropping system to control root-knot nematodes.     

中国大豆孢囊线虫抗性研究进展

中国是大豆的故乡,曾经是世界上最主要的大豆生产国和出口国。如今,中国的大豆生产量已从世界首位降到美国、巴西之后,由大豆出口国变为大豆进口国,其主要的原因之一是中国大豆生产未能有效的控制大豆孢囊线虫的危害,以致中国大豆平均单产处于较低水平。大豆孢囊线虫(Soybean Cyst Nematode,简称SCN)是一种土传的定居性内寄生线虫,大豆孢囊线虫的二龄幼虫从根尖处侵入根部,造成根组织的代谢失调与组织损伤,受害的大豆根系短粗,植株矮小,叶片变黄,产量严重降低。SCN的特点是分布广、危害重、寄主范围宽、传播途径多,存活时间长,防治极难。SCN危害已遍及中国大豆主要生产区,主要分布在我国的东北大豆主产区的黑龙江、吉林、辽宁、内蒙古及黄淮海大豆主产区的山东、河北、山西、安徽、河南、北京等省市,每年SCN发生面积达150万hm^2以上。本文综述了近年来我国在大豆孢囊线虫研究方面取得的进展,主要包括以下几个方面：SCN生理小种的研究、SCN抗性资源发掘、SCN经典遗传及分子遗传学研究及SCN抗性育种等研究进展。     

咖啡锈菌生理小种的研究进展及我国咖啡锈菌生理小种变化的动态预测

综述了世界咖啡锈菌生理小种的研究进展,并对我国咖啡锈菌生理小种变化的动态进行预测     

广东省稻瘟病菌生理小种的消长动态

１９９０～１９９７年,用中国稻瘟病菌鉴别寄主鉴定了广东省稻瘟病菌单孢菌株１５７４份,共鉴定出８群４３个生理小种。其中ＺＣ群一直是广东省的优势种群,其出现频率平均为５０２％;ＺＣ１３一直是优势小种,其出现频率平均为２７４％,其次是ＺＧ１（１８８％）、ＺＣ１５（１４５％）和ＺＢ１３（９１％）小种。不同地区不同年份优势小种的类型及其组成不同。