Effects of Different Tree Species on Growth and Yield of Mung Bean (Vigna radiata (L.) Wilczek) Grown in Hedgerow Intercropping Systems in Sri Lanka

Reduction of crop yields due to resource competition from tree hedges is a serious drawback of hedgerow intercropping. This work quantified the competition of six potential hedgerow tree species ( Calliandra calothyrus , Desmodium ransonii , Flemingia congesta , Gliricidia sepium , Cassia spectabilis and Tithonia diversifolia ) on mung bean ( Vigna radiata ) grown as hedgerow intercrops at Pallekelle in the mid-elevational (367 m above sea level), subhumid (rainfall of 1400 mm year⁻¹) zone of Sri Lanka. Leaf area, total biomass and yield of mung bean in hedgerow intercrops showed a clear reduction closer to the hedgerows, whereas no such reduction was observed in a sole crop of mung bean. At 30 cm from the hedgerow, growth and yield of mung bean were significantly lower than in the sole crop, indicating significant competition from hedgerows. However, growth and yield of mung bean increased with increasing distance from hedgerows so that, at 150 cm, mung bean under Gliricidia and Desmodium showed significantly greater growth and yields than the control. In contrast, even the maximum mung bean yields under the rest of the species did not reach that of the control. The differences in competition with different hedgerow species are discussed in terms of variations between tree species in biomass production, quality of prunings and the possibility of root competition.     

辣椒DH群体果实性状的分离及与F2群体的比较

为分析DH群体的遗传稳定性及其DH群体内性状分离与同来源的F2群体之间异同，本研究利用辣椒花药培养技术，构建一个由“羊角椒(97403)×方灯笼甜椒(97410)”的杂交而成的牛角椒组合作为供体的且由103个DH系组成的DH群体，对该DH群体进行单果重等5个主要果实性状的遗传表现进行分析，并与同来源的F2群体进行比较。结果表明：原供体及其双亲的5个果实性状的变异系数均较小，三者之间的各性状均存在显著差异，说明原供体及其双亲的整齐一致性；对DH群体和F2群体各性状的平均值、变异系数及其性状分离区间的分析和对比结果表明，5个果实性状均是受多基因控制的数量性状，且由于基因重组无论是DH群体还是F2群体均能产生正向和负向两个方向的超亲基因型。但DH群体与F2群体比较各性状的分离区间明显增大，超亲分离类型明显增加，且获得的各DH系均为稳定遗传的自交系，提高了花培育种的选择效率。     

Anther-culture response in different genotypes and F1 hybrids of pepper (Capsicum annuum L.)

An in vitro anther-culture method has been improved by using young mother plants and by using frequent subcultures, thus increasing the androgenic yield in different Capsicum annuum L. genotypes. An assortment of peppers was used, composed of 15 genotypes (four breeding lines, seven cultivars and four F₁ hybrids). A new system for qualifying the androgenic response was established. For use in practical breeding, a minimum of 5 % of plant regeneration was proposed as the criterion for a fair response. Accordingly, one excellent, one good and eight fair responses were identified among the genotypes investigated. As compared to the standard cultivar. 2 genotypes gave a significantly better response, i.e. ‘Fehérözön’ (75.8%) and ‘Szechuan 90716’ (21.0%). In comparative investigations, F₁ hybrids, produced from crosses between poor/non-responsive and responsive genotypes, showed a fair level of response, even the case of a poor response in donor parent. The ploidy level of the resulting plants was determined by flow-cytometric analysis.     

Effect of Water Stress on the Lipid and Fatty Acid Composition of Sweet Pepper (Capsicum annuum L.)

Sweet pepper ( Capsicum annuum L.) plants were grown under field irrigation and dryland conditions. Stress was imposed 12 d after planting by withholding water for 8 d, and seedlings were harvested for analysis 20 d after planting. In stressed plants, leaf water potential dropped from -0.65 to - 1.03 MPa and water saturation deficit increased by 40 %; plant height did not show a significant reduction. The fresh and dry weights of stressed seedlings and their ratio decreased. The total lipid and total phosphorus contents of stressed seedlings decreased by about 43 % and 71 %, respectively, in comparison to the contents of the watered seedlings. The diacylglycerol, free fatty acid and total polar lipid contents decreased significantly with stress, the last mentioned by more than 50 % in phospholipid levels. Glycolipid levels; were unchanged and the amount of triacylglycerol increase by about 30 % over the control.
Despite the differences found in the fatty acid composition of various lipid classes and between treatments, the degree of unsaturation did not change significantly either in control or stressed seedlings. Under stress conditions, free sterol levels increased without showing any change in the ratio of 'more planar' to 'less planar' sterols. The increase in free sterols and the decrease in phospholipid levels under water deficit conditions raised the sterol/phospholipid molar ratio 3-fold. The different responses of the lipid classes to water deficits and their possible significance are discussed.     

Graft-induced variants as a source of novel characteristics in the breeding of pepper (Capsicum annuum L.)

A line with genetic changes that was obtained from selfed seeds of the scion of an intraspecific pepper graft was used as a source of new characteristics in this breeding experiment. Five new variant lines and several sublines were bred by the use of this graft-induced variant strain and two other cultivars. Gradual introduction of the desired quantitative traits and selection resulted in combinations which significantly outperform the parental lines. Our breeding aim was to combine the two-lobed fruit shape that is characteristic for the graft-induced variants with thick pericarp, high sugar content, large fruit size, and significantly reduced or eliminated pungency in the new variants. A bushy plant type, typical for the graft-induced variants could be maintained in some selected sublines. The use of the three different genotypes resulted in many favorable combinations of quantitative traits, and lines were selected with the most valuable new characteristics. However, not all of these expressed the two-lobed fruit apex of the graft-induced variants. Our results reveal that the new characteristics which are induced by grafting are stable, new traits, and can be used as a novel genetic source in the breeding of pepper. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetics of Seed Yield and its Components in Common Bean (Phaseolus vulgaris L.) of Middle-American Origin

Genetic variance, heritability, and expected response from selection arc useful in devising alternative methods and criteria of: selection. The objectives of this study were to estimate these for seed yield and its components from 200 F₂: populations involving 80 cultivars and lines of mostly small-seeded dry bush bean (Phaseolus vulgaris L.) of habits growth I, II, and III of Middle-American origin. All cultivars and lines were crossed in eight sets of ten parents each in a Design II mating system. The F₂ populations, without parents, were evaluated in the field in a replicates-in-sets design at two locations in Colombia in 1983. Estimates of additive genetic variance were significant for yield, pods/m², seeds/pod, and seed weight. Interaction with environments was also significant. Values for nonadditive genetic variance were not significant for either yield or yield components. The estimates of narrow sense heritability, based on the F₂ population mean and unbiased by genotype x environment interaction, were 0.21 ± 0.13 for yield. 20 ± 0.13 for pods/m², 0.57 ± 0.13 for seeds/pod, and 0.74 ± 0.15 for seed weight. The expected direct response from selection of the top 20 % of F₂ populations for yield per se would result in a 4.30 % increase in yield with a correlated response of 0.21 % in seed weight. In contrast, the expected gain from direct selection for seed weight would result in a 11.76 % increase in seed weight with a, correlated gain of 0.28 % for yield. Direct selection for pods/m² would decrease yield, seeds/pod and seed weight, while direct selection for seeds/pod would reduce pods/m² and seed weight but increase seed yield by 0.37 %. Data on yield from replicated trials in the early segregating generations could be utilized for identification and selection of promising crosses and families or lines with crosses for dry bean yield improvement.     

Influence of Phytohemagglutinin on the Agronomic Performance of Beans (Phaseolus vulgaris L.)

The abundant lectin phytohemagglutinin (10 % of total seed protein) does not contain sulfur amino acids and, being a potent antimetabolite, it is responsible for the lowering of the nutritional value of bean seeds. The aim of the present work was to improve the dry bean cultivar ‘Taylor's Horticultural’ (Asgrow), by genetically introducing the lectin null (lec/lec) character from two null genotypes: ‘Pinto UI 111’ and ‘Heidi’. Thirty-seven BC²F₃ and fourteen BC₆F₅ inbred lines were evaluated in agronomical trials. Analysis of Variance (ANOVA) showed significant differences among BC₂F₃ breedings lines for all traits under evaluation. Comparison of the LedLee genotypes versus lec/lec did not show statistically significant differences in the means for the following traits: yield, yield components and percentage of protein in the seed. Fourteen BC6F5 lines, compared together with their recurrent parent ‘Taylor's Horticultural’, showed significant differences among genotypes for 1000 seed weight, protein percentage on dry matter and ash percentage. No significant differences were observed for grain yield. The data indicate that lectin removal did not have a detrimental effect on the traits evaluated.     

3个辣椒花药培养再生株群体主要农艺性状及苗期抗病性研究

对3个辣椒花药培养再生株DH-R2群体的主要农艺性状,包括株高、株幅、首花节位、叶色、单果质量、商品果横径、商品果纵径、果形指数、老熟果色等进行了较详细的测量和统计分析。结果表明:辣椒花药培养再生株群体的农艺性状存在基因型偏性;再生株群体的单果质量、商品果纵径、果形指数这3个性状都表现为低于供体,株高、株幅、首花节位、商品果横径这4个性状都表现为近似于供体;通过单倍体培养途径可以得到不同颜色层次的老熟果色的辣椒纯系,证明了该途径是多基因控制性状育种的有效途径;对耐TMV和CMV的亲本与感病亲本的杂种进行花药培养,获得了兼具TMV和CMV抗性的株系,证明了单倍体培养途径可以创造新的超亲抗病种质。     

间作和双接种对玉米和菜豆生长的影响

为了验证菜豆玉米间作的可行性及双接种丛枝菌根真菌和根瘤菌在此间作体系中的影响。通过采用盆栽试验的方式,测定了不同栽培及接种方式下玉米和菜豆的一些生理指标如：生物量、氮磷钾元素的含量及吸收量、叶绿素SPAD值、菌根侵染率等。结果表明：单接种时,单作下的玉米和菜豆的总生物量分别是间作下的3.26 倍和1.25 倍;双接种时也分别达到了3.08 倍和1.25 倍。然而单接种时玉米和菜豆间作后每盆的吸氮量和吸磷量分别是间作下的1.11 倍和1.05 倍;双接种时则均为1.16 倍。接种丛枝菌根真菌后玉米及菜豆的生物量、氮磷钾元素的含量及吸收量、叶绿素含量等差异均不显著,而菜豆的根瘤数却降低了。试验研究表明：间作抑制了菜豆及玉米的生长,但促进了二者对氮磷元素的吸收利用;接种丛枝菌根真菌对玉米及菜的生长无促进作用,对二者吸收利用氮磷钾元素也无明显促进,而且还抑制了根瘤菌侵染菜豆。     

海南高产甜椒杂交制种技术研究

对海南特定气候特点下影响甜椒杂交制种的几个环节进行了详细研究，结果表明：以开花前1d去雄、第2d早上授粉单果饱满种子数最多；摄子去雄、不去花瓣，摄子去雄、去部分花瓣，徒手去雄3种去雄方法对座果率、种子数差异不显著；空气相对湿度大于70%，温度25~30℃花粉发芽率较高；完全转色种果的种子发芽率最高，后熟作用对发芽率影响不大，而始转色果和绿熟果随着后熟时间的增加，发芽率逐渐升高；完熟果种子在常温保存200d后发芽率几乎不变，而绿熟果和始转色果则下降较快。针对上述结果，提出了提高制种纯度和产量的相关方案和措施。     

Environmental Interactions between Different Tree Species and Mung Bean (Vigna radiata (L.) Wilczek) in Hedgerow Intercropping Systems in Sri Lanka

Annual crops grown in association with contour hedgerows often show yield reductions. This paper quantifies the variation of above- and below-ground environmental factors in hedgerow intercrops involving six different tree species ( Calliandra calothyrus , Desmodium ransonii , Flemingia c ongesta , Gliricidia sepium , Cassia spectabilis and Tithonia diversifolia ) and thereby shows the effects of tree hedges on mung bean ( Vigna radiata ). Compared to a sole crop of mung bean, most hedgerow intercrops removed greater soil nitrogen, whereas all removed lower soil phosphorus. Mung bean closer to the hedgerows had lower N and P, indicating competitive capture of nutrients by hedges. Most hedgerow intercrops had greater top-soil water because of their shading effect, especially near hedgerows. However, greater absorption by tree root systems decreased subsoil water near hedgerows late in the season. Soil temperature was lower in most hedgerow intercrops than in the control and increased with increasing distance from hedges. During initial stages of mung bean growth, radiation interception of intercrops was greater than that of the control, especially closer to hedgerows. However, after the first month, radiation interception of the sole crop was either equal to or greater than that of hedgerow intercrops. There was significant variation between tree species in all these environmental factors. Gliricidia , which allowed greater mung bean yields, also allowed greater nutrient capture by mung bean, greater top-soil water availability, lower extraction of subsoil water and lower soil temperatures.     

Patterns of genetic diversity in landraces of common bean (Phaseolus vulgaris L.) from Galicia

Knowledge of patterns of genetic diversity among existing cultivars helps to broaden the genetic base of new cultivars and maximizes the use of available germplasm resources. This study examined the organization of diversity for morphological traits in 66 landraces of cultivated common bean (Phaseolus vulgaris) from Galicia and its relationship with phaseolin seed protein diversity. Data on growth habit, seed and pod traits obtained from field evaluations at two locations during the 1989—91 cropping seasons were subjected to multivariate statistical analysis. Cluster analysis based on 14 quantitative variables and five qualitative variables identified 11 groups. The landraces were also characterized by phaseolin electrophoresis. The results allowed separation of these landraces into Middle and Andean American groups, which could be further divided into at least eight groups within the Andean American cultivars and three within the Mesoamerican cultivars. These groups in turn corresponded to the previously described races Nueva Granada and Peru of South American origin, and races Durango, Jalisco and Mesoamerica from the Middle American domestication centre. These results confirm the existence of two major groups of germplasm in the cultivated common bean landraces from Galicia, Mesoamerican vs. Andean American.     

加工型辣椒花药培养技术研究

为了满足重庆辣椒高效育种与良种创新的需要,以2个加工型辣椒材料578和186及一个甜椒品种‘海丰28’为试材进行花药培养研究。研究了预处理与预培养的时间与温度,并通过正交试验设计,探讨了基本培养基、植物生长调节物质、活性炭、硝酸银、碳源等主要因子对辣椒花药培养的影响。结果表明,高温预培养35℃7天时辣椒578、186、甜椒‘海丰28’的植株诱导率分别为4.86%、2.50%、0.56%,是对3种材料都适合的预培养条件。通过正交试验分析得到对2个基因型特异的优化培养基配方,并且通过比较得到一个对2个基因型都较适合的培养基配方。对花药培养再生的植株进行倍性鉴定,证明3个基因型均得到了具有12条染色体的单倍体植株。以饱和对二氯苯与0.2%秋水仙素浸泡生长点24 h进行加倍,成功获得了双单倍体植株。     

Independent, Alternate, and Simultaneous Selection for Resistance to Anthracnose and Angular Leaf Spot and Effects on Seed Yield in Common Bean (Phaseolus vulgaris L.)

Two double-cross populations were used to evaluate the efficiency of independent, alternate, and simultaneous selection practiced from the F₂ to F₈ for resistance to anthracnose and angular leaf spot of common bean (Phaseolus vulgaris L.). Seven resistant and high-yielding lines were selected from each of the four environments used during this study. These lines and the seven parents involved in two populations were evaluated in an 8 × 8 lattice design with three replications in two cropping seasons. Pathogen inoculum was used to create the three test environments: anthracnose alone, angular leaf spot alone, and anthracnose and angular leaf spot together. All entries were also evaluated in a fourth, disease-free environment. Selection for resistance to anthracnose and angular leaf spot was effective in both populations. Mean disease scores of all selected lines for anthracnose were lower than that of angular leaf spot irrespective of selection environment. Among the three stress environments, yields were higher in the anthracnose environment. However, lines selected alternately for anthracnose and angular leaf spot were usually higher yielding, and the highest yielding line in both populations originated from this selection environment. The mean yield of selected lines was higher and the highest yielding line originated from the population involving a parent (G 1805) belonging to the Mexican highland race ‘Jalisco’. Positive association existed between seed yield of protected and pathogen-inoculated environments. No association was found between resistance to anthracnose and angular leaf spot.     

AFLP Analysis of Mitochondrial DNA from a Cytoplasmic Male Sterility Line and its Maintainer in Pepper （Capsicum annuum L.）

Cytoplasmic male sterility （CMS） is a maternally inherited trait characterized by the inability of a plant to produce functional pollen, which is widespread among higher plants. CMS system is a valuable tool for plant brc, ders to utilize in hybrid seed production and for molecular biologists to study the interaction between nuclear and mitochondrial genomes. Investigations into the molecular mechanism of CMS in several species have revealed that the incompatible nuclear-mitochondrial interactions leading to new chimeric mitochondrial genes such as T-urfl3 for Texas male sterility cytoplasm in maize, pcfin petunia, orf522 in sunflower, orf107 in sorghum and orf244 gene in Brassica may be responsible for CMS （Dewey et al., 1986; 1987; Young and Hanson,1987; Nivison and Hanson, 1989; Kohler et al., 1991; Moneger et al., 1994; Tang et al., 1996; Handa et al., 1995; Singh and Brown, 1991）.     

秋水仙素对辣椒生长的影响及多倍体诱导效应研究

以秋水仙素为诱变剂,比较了不同浓度和不同处理时长组合下辣椒(Capsicum annuum L.)的生长差异和多倍体诱导效应.结果表明:和对照植株相比,所有处理变异植株在形态上表现为叶片宽大,叶色较深,茎变粗且节间距长,气孔增大;相关指标都表现出显著或极显著的差异,而且随着处理强度的增加差异更为明显.秋水仙素诱导产生的变异植株经染色体倍性鉴定植株表征为嵌合体(2 n=24或2 n=48).相同处理时长下,不同浓度秋水仙素溶液对辣椒多倍体诱导效应差异显著,而对相同浓度下不同处理时长对植株叶片数和气孔面积影响差异不显著(P>0.05),其它指标差异极显著(P<0.01).秋水仙素浓度与处理时长之间存在交互作用,不同处理之间除气孔面积差异不显著之外,其它指标间差异显著或极显著.结合加倍率和植株死亡率综合分析后认为,用0.05%的秋水仙素溶液处理6天诱导效果最佳,诱导诱导加倍率可达26.1%.     

Phenotypic variation in a core collection of common bean (Phaseolus vulgaris L.) in the Netherlands

Forty accessions, forming a core collection of mainly bush type of the common bean (Phaseolus vulgaris L.) germplasm in the Netherlands, were evaluated for 14 qualitative and quantitative traits at the Agricultural University, Wageningen (WAU), the Netherlands in 1992. These and an additional 117 Dutch accessions, mainly collected in private home gardens, were also evaluated for phaseolin seed protein pattern, and morphological and agronomic traits at the International Center for Tropical Agriculture (CIAT, Spanish acronym), Cali, Columbia between 1987 and 1997. Multivariate and principal component analyses at both WAU and CIAT indicated existence of one large group with no discernable patterns among Dutch common bean collections of landraces, garden forms and cultivars. However, when phaseolin, an evolutionary, biochemical marker, was used as an initial classification criterion followed by use of morphological markers, the two major gene pools; Andean and Middle American with two races in each (Chile and Nueva Granada in Andean, and Durango and Mesoamerica in Middle American) were identified. The Andean gene pool was predominant (136 of 157 accessions), especially the race Nueva Granada (126 accessions) characterized by the bush determinate growth habit type I and T phaseolin. The new core collection comprised 31 accessions. Bean races Chile, Durango, and Mesoamerica were represented by 10, 7, and 14 accessions, respectively. Of the 9 French or snap bean accessions six possessed characteristics of race Mesoamerica and three belonged to Durango race. Occurrence of these and a large number of other recombinants strongly suggested considerable hybridization and gene exchange between Andean and Middle American gene pools, thus blurring the natural boundaries and forming a large single group of common bean germplasm in the Netherlands. The inter-gene-pool recombinants of both dry and French beans should be of special interest to breeders for use as bridging-parents for development of broad-based populations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Location-Specific and Across-Location Selections for Seed Yield in Populations of Common Bean, Phaseolus vulgaris L.

Two populations of common bean, Phaseolus vulgaris L., were used to make three independent location-specific selections at Palmira, Quilichao, and Popayán, Colombia. Also, three across-location selections were made by alternating generations between Palmira and Popayan, between Quilichao and Popayán, and among Palmira, Quilichao, and Popayán. The seven highest yielding lines selected from each environment and population along with 14 parents and two checks were evaluated for seed yield, seed weight, maturity, and reaction to an-thracnose, angular leaf spot, and common bacterial blight. Mean squares due to evaluation and selection environments, selected lines, and their interactions were significant for all traits. Mean yields of selected lines were higher than the mean of parents in both populations. Among location-specific selections, lines yielded higher at their respective selection site. Moreover, selections made at Popayán were higher yielding than those made at Quilichao or Palmira when tested across locations and years. Use of Popayán, a relatively wetter and cooler site, either alone or in combination with other locations resulted in higher yield, higher seed weight, and higher resistance to anthracnose. On the average, location-specific selections were lower yielding than the across-location selections. Among across-location selections, those selected between Palmira and Popayán were the highest yielding in both populations. Selections at Palmira and across all three locations resulted in greater stability.     

辣椒花药培养再生株群体染色体倍性构成的多样性

采用流式细胞分析术和染色体计数法对辣椒花药培养再生株群体的染色体倍性构成情况进行了鉴定。显示了花药培养再生株中染色体倍性构成的多样性。观察到染色体倍性在不同检测组织器官中的差异现象,说明对同一材料不同器官进行倍性检测以确定植株倍性的必要性,以及植株上部器官的染色体倍性对于结籽能力的决定性。观察到再生株中个别细胞染色体的丢失现象。对流式细胞检测技术和染色体计数法的相关性进行了研究,得出2种检测技术下二者的吻合度为0.95,并对流式检测技术中的偏峰现象进行了初步的分析。     

Breeding for yield, in mixtures of common beans (Phaseolus vulgaris L.) and maize (Zea mays L.)

Summary Despite the growing industrialization, technification and transformation that is happening in the agriculture around the world, and despite that agricultural research has always concentrated its effort on sole crops, multiple cropping systems have historically been important for common bean production in tropical countries. The reasons for this fact, are economical and social, as well as biological. Bean breeders have always been questioned on their work, because the development of new varieties is usually done in sole crop, but the varieties are grown in either systems. This paper addresses a set of questions that are usually presented to the breeders, in light of the evidence obtained from many trials conducted in Brazil and in the U.S.A.: Will the genotypes bred for sole crop conditions, perform well when grown in intercrop; How different should a genotype be, for cultivation in intercropping compared to genotypes developed for sole crop conditions; Is there a need for special breeding programs for intercropping and How could a breeding program focus the question of multiple (associated) cropping?