Diversity among melon landraces (Cucumis melo L.) from Greece and their genetic relationships with other melon germplasm of diverse origins

Diversity among 17 melon landraces and inbred lines of Group Cantalupensis, Inodorus, and Flexuosus germplasm from Greece was assessed using 24 RAPD primers, 11 morphological traits of fruit, two yield-related characteristics, and resistance to powdery mildew. Accessions were genetically diverse and the greatest variation was detected in Group Flexuosus. Comparative analysis of Greek germplasm and an array of previously characterized reference accessions [RA; 68 from Africa (15), United States (U.S.; 5), Central Europe (14), Japan (19), and Spain (15)], spanning major market classes employing 19 RAPD primers (standard marker array), indicates that all but one of the accessions from Greece showed genetic affinities among themselves and with 23 RA of various origin (i.e., Japan, U.S., Central Europe, Spain and Israel) and market class. Accessions from Greece were, however, distinct from the African landraces and most Spanish melons. Greek accessions also showed little genetic affinity with the Casabas (Blanco and Crenshaw), Ogen, and U.S. Eastern Market accessions. Group Flexuosus and Inodorus accessions from Greece possessed genetic affinities with Western Asian (Group Conomon) and Mediterranean (Group Inodorus) market classes, respectively. The uniqueness of Greek melon landraces portends their potential usefulness for the enhancement of U.S., European, and Asian melon market classes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic diversity evaluation of a loquat (<Emphasis Type="Italic">Eriobotrya japonica</Emphasis> (Thunb) Lindl) germplasm collection by SSRs and <Emphasis Type="Italic">S</Emphasis>-allele fragments

Loquat (Eriobotrya japonica (Thunb.) Lindl.) is a minor Rosaceae fruit of growing interest as an alternative to the main fruit crops. In this context, the selection of new cultivars to satisfy the market demand will request the suitable characterization of the available germplasm. In this work, genetic relationships among 83 loquat accessions from different countries belonging to the European loquat germplasm collection, held at the Instituto Valenciano de Investigaciones Agrarias (IVIA) in Moncada (Spain) were evaluated using microsatellites and S-allele fragments. A total of nine single sequence repeats (SSRs) from Malus and Eriobotrya genera revealed 53 informative alleles and the S-RNases consensus primers detected 11 self-incompatibility putative alleles. The combined data allow to distinguish unambiguously 80 out of the 83 accessions studied. Unweighted pair-group method (UPGMA) cluster and principal coordinates analysis (PCoA), based on Dice’s genetic distance, generally grouped genotypes according to their geographic origins and pedigrees. Discrepancies and similarities of the results obtained with other variability analysis, based on pomological traits or molecular markers, on the same loquat collection are discussed.     

Diversity in a pea (<Emphasis Type="Italic">Pisum sativum</Emphasis>) world collection for key agronomic traits in a rain-fed environment of Southern Europe

The marked underutilization of pea ecotype and old cultivar genetic resources need be reversed by producing information on elite germplasm and diversity patterns for key agronomic traits. This study generated such information for a world collection of 223 ecotypes or old cultivars of P. sativum subsp. sativum subdivided into 19 regional pools (each represented by 9–15 entries) and one reference pool of 11 locally-adapted varieties from France, Spain and Germany. The collection was evaluated for grain yield, seed protein content, straw biomass, phenology and other agronomic and morphological traits in a spring-sown, water-limited environment of Northern Italy. Variation within ecotype/old cultivar germplasm pools was at least two-fold greater for seed size and protein content and seven-fold greater for other traits relative to variation between pools, and was particularly large within pools from Central Europe, Near East and United Kingdom. The traditional germplasm, compared with improved variety material, tended to display higher dry grain yield (1.11 vs. 0.85 t/ha) and straw biomass, later crop maturity, smaller seed, and similar protein content. Traditional germplasm from Central Europe combined outstanding grain yield and total biomass with high seed protein content. High grain yield characterized, inter alia, the germplasm pools from Ukraine and Spain, the latter also featuring high protein content. Several ecotype/old cultivar accessions out-performed (P < 0.05) the best-ranking varieties for grain yield or protein content. Patterns of phenotypic variation were poorly related to geographic origin of germplasm pools, while highlighting the distinctness of improved variety germplasm.     

软枣猕猴桃种质资源果实品质、表型性状多样性及主成分分析

为更好的分析、评价软枣猕猴桃种质资源多样性,对70份种质资源果实的15个性状指标进行了相关性及主成分分析。结果表明,种质间各性状变异幅度较大,类型丰富。相关性分析结果表明,一些果实性状间存在显著或极显著相关;主成分分析结果表明各性状的贡献率分散,性状变异具有多向性。其中,第1主成分主要由果实质量、果实纵径、横径、侧径及果梗长决定,第2主成分主要由果皮颜色、表皮光滑度及果形指数决定,第3主成分主要代表可溶性糖含量、可溶性固形物及维生素C含量,第4主成分反映了果实可滴定酸含量情况。因此在软枣猕猴桃育种改良过程中,第1主成分增大时有利于增大果实大小,第3主成分增大时有利于提高果实品质。     

黄秋葵种质资源遗传多样性及相关性分析

为有效地利用黄秋葵种质资源,给新品种选育提供理论依据,以60份黄秋葵种质资源为试验材料,对31个植物学特征和生物学特性指标进行了遗传多样性分析和相关性分析。结果表明:(1)黄秋葵植物学特征间存在明显相关性,茎色、茎表面、叶色、果色呈同一对应关系。叶姿越直立的,其叶型多为浅裂叶或全叶,花冠中等偏小,种子形状多是圆形;反之,叶姿下垂的,叶型多为深裂叶,花冠较大,种子多为扁圆形、肾形。(2)黄秋葵的生物学特性多样性丰富,存在广泛变异,其变异系数排序为:种子产量(72.51%)果数(43.84%)叶柄长(40.84%)果长(36.95%)第1朵花开花天数(28.22%)叶片长度(22.69%)叶片宽度(21.28%)分枝数(21.05%)株高(20.99%)开花天数(18.14%)出苗天数(16.96%)生育天数(8.97%)花瓣数(2.57%)。(3)黄秋葵生物学特性间存在明显相关性,黄秋葵种子产量与叶柄长度、果数、叶片长度、叶片宽度、开花天数达极显著正相关,相关系数分别为0.53、0.49、0.46、0.39、0.37。开展黄秋葵种质遗传多样性的研究对黄秋葵种质的鉴定、评价及利用有着重要的意义。     

The nabicol: A horticultural crop in northwestern Spain

Nabicol (B. napus L. var. pabularia) is a traditional crop in the Northwest of Iberian Peninsula (South of Galicia and North of Portugal) where it is grown during the winter season on small farms and gardens using traditional varieties. A collection of 36 populations of nabicol from Galicia (northwestern Spain) was evaluated during 2002 and 2003 in two locations and two growing seasons (spring/summer and autumn/spring) for 28 agronomic and morphological traits. The objectives of this study were to: (i) evaluate a collection of nabicol landraces from northwestern Spain, (ii) determine the suitability of this germplasm as a summer crop and (iii) study the genetic diversity among local populations. Significant differences were observed among populations for most traits. Genotype × environment interaction was significant for most of them. Spring/summer growing season could be recommended for growing nabicol but resistance to Lepidoptera pests attacking Brassica crops should be improved. Most populations had an agronomic value similar to the commercial variety. The most promising variety for horticultural use was MBG-BRS0063, which showed the highest yield. Morphological and agronomic data were subjected to cluster analysis and four groups were defined with a group clustering most populations. The low genetic diversity could be explained because populations were collected in close geographical areas and the selection made by farmers was always for a horticultural use. These results give information about the diversity and breeding value of the nabicol Spanish germplasm, which could be useful in breeding programs.     

Multivariate analysis of vineyard peach [Prunus persica (L.) Batsch.] germplasm collection

Thirty vineyard peach [Prunus persica (L.) Batsch.] genotypes were studied to determine the overall degree of polymorphism and to detect similarities among genotypes. The variation was observed for traits related to phenology, morphology, yield and fruit quality. Many fruit characteristics that are important to breeders are present in this collection. The majority of important correlations were determined between the characteristics representing fruit size (fruit width, fruit height, fruit weight and stone weight) and between those ones representing fruit quality (fruit attractiveness, taste, flavour and soluble solids content). Cluster and principal component analysis showed a considerable phenotypical diversity in the vineyard peach germplasm. Clustering of genotypes was in accordance with its purpose (fresh consumption or rootstocks production). Parameters with high discriminating values were those related to fruit size and fruit quality.     

Biplot analysis of trait relations of white lupin in Spain

A 2-year study of autumn-sown white lupin (Lupinus albus L.) was conducted under rainfed Mediterranean conditions in southern Spain. 108 landraces were evaluated for yield and major phonological and plant structural characteristics. Path coefficient and Genotype-Trait (GT) biplot analysis were used. Applying both types of analyses to the multiple trait data revealed that GT biplot graphically displayed the interrelationships among traits and facilitated visual comparison of accessions and selection. Wide variation was observed for trait phenology (dates of flowering and maturity), plant structure (plant and first order inflorescence height) and yield characters (first order branches, first order inflorescence and total yield). It was found that the accessions with the highest yields were the tallest and the latest to flower, both on the mainstem and on the lowest first order branch, and also were the latest to mature. GT biplots also had suggested as the accessions have been displayed according to their origins. The results showed that foreign germplasm may be an important material for improving some yield components such as number of pods and seeds per plant of locally adapted lupins in Spain. This revised version was published online in July 2006 with corrections to the Cover Date.     

基于表型性状构建中国花生地方品种骨干种质

中国花生地方品种遗传多样性丰富,是花生新品种选育的重要亲本来源。本研究以种质库保存的2741份地方种质为材料,基于种植区划和植物学类型分组,平方根法确定取样量,组内按13个表型数据进行UPGMA聚类分析,类内随机取样,构建骨干种质。利用t检验、F测验、卡方测验、极差、表型保留比例、表型相关性等对骨干种质代表性进行检验和评价;并利用主成分分析和直方图对骨干种质进行确认。结果表明,构建了包含259份种质的中国花生地方品种骨干种质,占全部种质的9.4%,包括多粒型14份、珍珠豆型85份、龙生型42份、普通型103份、中间型15份。在P 0.05概率条件下,骨干种质13个性状的均值、方差、变异系数、香农指数与全部种质无显著差异,且保留了全部种质的分布范围、表型保留比例和表型相关性;二者的植物学类型组成和生态分布是一致的,具有相似的遗传结构和分布频率。建立的骨干种质很好地代表了全部种质的遗传变异和群体结构,可为花生种质创新和优异等位基因发掘奠定良好的基础。     

Evaluation of soybean germplasm conserved in NIAS genebank and development of mini core collections

Genetic variation and population structure among 1603 soybean accessions, consisted of 832 Japanese landraces, 109 old and 57 recent Japanese varieties, 341 landrace from 16 Asian countries and 264 wild soybean accessions, were characterized using 191 SNP markers. Although gene diversity of Japanese soybean germplasm was slight lower than that of exotic soybean germplasm, population differentiation and clustering analyses indicated clear genetic differentiation among Japanese cultivated soybeans, exotic cultivated soybeans and wild soybeans. Nine hundred ninety eight Japanese accessions were separated to a certain extent into groups corresponding to their agro-morphologic characteristics such as photosensitivity and seed characteristics rather than their geographical origin. Based on the assessment of the SNP markers and several agro-morphologic traits, accessions that retain gene diversity of the whole collection were selected to develop several soybean sets of different sizes using an heuristic approach; a minimum of 12 accessions can represent the observed gene diversity; a mini-core collection of 96 accession can represent a major proportion of both geographic origin and agro-morphologic trait variation. These selected sets of germplasm will provide an effective platform for enhancing soybean diversity studies and assist in finding novel traits for crop improvement.     

Fruit antioxidant capacity and self-incompatibility genotype of Ukrainian sweet cherry (Prunus avium L.) cultivars highlight their breeding prospects

Breeding for higher levels of health-promoting components are among the priorities for many fruit crops. Such an approach requires breeding material displaying great variations in the trait to be improved. Commercial sweet cherry cultivars demonstrate only limited variability in fruit antioxidant parameters and hence this study was carried out to characterize some Ukrainian sweet cherry cultivars for their antioxidant and antiradical capacity and total phenolic and anthocyanin contents. Ukrainian cultivars had significantly higher ferric reducing antioxidant power and total phenolic contents compared with commercial cultivars. Levels of all four parameters varied considerably in the Ukrainian germplasm, with some cultivars having outstanding values. A total of eight different self-incompatibility genotypes were assigned to the 14 accessions tested. Assigning cultivars to the appropriate incompatibility groups allowed the design of parental combinations which may result in new genotypes with enhanced functional properties and other valuable fruit traits. Based on the S-genotypes, parental combinations were proposed to ensure 50 or 100 % self-compatible seedlings in the offspring population. The most perspective Ukrainian cultivars like ‘Dagestanka’ and ‘Kodrinskaya’ also had reasonable fruit weight (over 8 g), high flesh to pit ratio (approx. 18) and soluble solid contents (over 16 %). Our results demonstrated that adequate variation is available in Ukrainian germplasm for improving fruit health benefits in sweet cherry through directed hybridizations.     

Mining Elite Sea-Island Cotton Germplasm Based on Phenotyping and SSR Markers

[Objective] An elite germplasm resource of sea-island cotton with outstanding traits was mined in order to accelerate the breeding process of new varieties. [Method] The core collections of sea-island cotton germplasm consisted of 178 accessions were used as experimental materials in this study. Analyses of variability and diversity were performed through detecting phenotypic data of six main breeding-targeted traits, including boll weight, boll number per plant, lint percentage, fiber length, fiber strength, and micronaire. The elite germplasm of sea-island cotton was selected according to 10% optimal sampling strategy based on the phenotypic value of each trait. The 120 pairs of polymorphic simple sequence repeat (SSR) primers were used to analyze the polymorphism of 178 accessions of the core collections. Then, we conducted the population structure and clustering analysis based on the genotyping results. According to the results of cluster analysis, the primary elite germplasm was further selected, and the final elite germplasm of sea-island cotton was identified. [Result] The results showed that there was a high variability and abundant genetic diversity in the 6 studied traits. In 178 accessions of sea-island cotton, 262 alleles were detected by 120 pairs of SSR primers, with an average of 2.18 loci. The average polymorphism information content (PIC) was 0.067 8-0.630 0, with an average of 0.296 0, showing moderate polymorphism. The cluster analysis showed that the core collection of sea-island cotton was divided into six groups. twenty-three elite germplasm resources of sea-island cotton were identified based on phenotypic value and cluster analysis of SSR markers. [Conclusion] The germplasm of sea-island cotton can be analyzed and evaluated based on the phenotyping and SSR markers, and then the elite germplasm of sea-island cotton can be identified. These results provided the material basis for the genetic breeding of sea-island cotton, as well as the important reference and basis for the mining and identification of crop elite germplasm.     

Phenotypic diversity and relationships of fruit quality traits in inter-specific almond × peach backcrosses breeding progenies

Nineteen agrochemical traits of 20 almond inter-specific backcrosses progenies were evaluated and compared for three consequence years to find out their phenotypic diversity and determine the relationships of fruit quality traits in almond × peach backcrosses breeding progenies. The variation was observed for traits of phenology parameters (blooming time, ripening time), Physical parameters (fruit weight, width, height, shape, thickness, skin pubescences, colour and flower type), chemical parameters (total sugar content, soluble solids content and acidity) and sensory parameters (attractiveness, taste, and flavor) and yield. Many fruit characteristics that are important to breeders are present in this collection. A high variability was found in the evaluated almond progenies and significant differences were found among them in all studied quality attributes. Year-by-year variations were observed for majority of traits. A significant correlation was found among the fruit height, fruit width, skin pubescences and yield. Fruit height showed a significant positive correlation with fruit weight and fruit thickness and some other traits and a negative correlation with the titratable acidity, skin pubescences and fruit flavour. A high negative correlation was found between the fruit weight and titratable acidity (?0.8). Low coefficients were got between the flower colour and skin pubescences. In addition, principal component analysis it possible to established similar groups of genotypes depending on their quality characteristics and to study relationships among pomological traits in almond progenies evaluated.     

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.     

Agronomical and quality traits of runner bean germplasm and implications for breeding

White runner bean landraces are greatly appreciated in the North highlands of Spain due to their excellent culinary seed quality. Runner bean cultivars are grown like pole beans. Diversity within a runner bean collection of 31 accessions from the Iberian Peninsula (Spain and Portugal) was examined using morphological, agronomical and seed quality traits. Landraces showed significant differences for most of the agronomical and seed quality traits studied except for seeds per pod, water absorption, seed coat tenderness and floury texture. Runner bean landraces showed sufficient variability to select inbred lines for future breeding. Genotype × environment interaction was significant for days to first flowering, days to first dry pod, seeds per pod and seed length. The majority of physical and nutritional seed quality traits studied which are important to determine the commercial value of a variety were not subject to environmental influences. Different selection pressures affecting to the runner bean genetic material could have occurred in several regions of the Iberian Peninsula. Extra-large and high yielding runner bean germplasm was identified and represents a valuable source of genetic diversity that has potential for development of improved cultivars to be chosen for commercialisation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genotype by environment interactions and combining ability for strawberry families grown in diverse environments

Ten seedlings from 36 crosses representing eastern and western North American short day and remontant genotypes were evaluated in 2011 and 2012 in California, Michigan, New Hampshire and Oregon, for phenology, flower related traits, plant characteristics, fruit characteristics and fruit chemistry traits. There was significant variability among genotypes, locations and evaluation year for most of the characteristics; however, few genotype × location and genotype × year interactions were detected. General combining ability variance components were significant for all traits and greater than SCA variance components for peduncle length, total flowering weeks, flowering cycles, truss size, growing degree days for harvest data, remontancy, achene position, ease of capping, fruit weight, percent soluble solids, titratable acidity and soluble solids/titratable acidity. ‘Sarian’ was identified as the best contributing parent for remontancy. Narrow-sense heritability estimates were moderate to high (0.33–0.78) for total flowering weeks, flowering cycle, truss size, remontancy, number of runners, fruit weight, pH, and titratable acidity. Having a better understanding of these attributes will provide breeders guidance on the most effective breeding strategies for incorporating superior traits from this germplasm into their programs.     

杧果种质部分生物学性状指标评价分析

摘要 对杧果树10个主要生物学性状指标主枝与主干夹角、叶片长度、叶片宽度、花序长、花序宽、两性花直径、雄花直径、果实长度、果实宽度、单果重进行了分析,发现其具有丰富的多样性,对包括叶形指数、果形指数在内的12个性状指标进行了分级或分类,提出了现阶段适用性更强的生物学评价参考标准,列出了具体的数据指标,提出了参照品种,为芒果种质资源的系统评价打下了一定基础。     

Genetic variation of a safflower germplasm collection grown as a winter crop in southern Spain

Summary A germplasm collection containing 23 accessions of safflower (Carthamus tinctorius L.) was sown in 1993/94 as a winter crop in southern Spain to perform a comparative evaluation. Morphological, physiological and chemical characters were evaluated. Considerable diversity was found in the group. Only one Mexican accession was dwarf (40 cm tall). Most accessions were spiny but there were two spineless Iranian accessions and others with few spines. Variations were also evident for head and seed size. Seed yield per plant varied from 2.5 to 103.5 g and it was correlated with the number of heads, number of branches and plant height. Cultivars with oil content over 35% were identified. Most accessions were of the high linoleic type but there were two with high or intermediate levels of oleic acid, corresponding to the cultivars Ole and Oleic leed. Sowing in November in southern Spain has produced a long growing period (180–240 days) but earliness is common in Indian accessions. A Chinese phenotype with a prolonged rosette stage could be better adapted for cold tolerance. Red flowered spineless cultivars were present in the collection and will be preferred for ornamental or dye purposes.     

Diversity evaluation of morphological traits and allicin content in garlic (Allium sativum L.) from China

China has a long history in garlic cultivation and is the biggest country of garlic production in the world. 375 accessions of garlic from 23 provinces and areas in China has been collected and preserved in national germplasm repository for vegetatively propagated vegetables in Beijing since 2002. However, the genetic background and diversity of garlic from China has not been well characterized. In this study, 212 of 375 accessions of garlic were evaluated based on 29 morphological traits and allicin content. Cluster, principal compound, principal ordinates, Shannon diversity index and Pearson correlation analysis were used. The results showed that the garlic clones from China had a widely diversity among all traits. Principal component analysis showed the cumulative proportion of the first eight components explained 71.35 % of total morphological variation in all accessions. Germplasm cluster analysis whether based on 29 morphological traits or bulb yield-related traits could distinguish all germplasm. All accessions were divided into two groups with bolting and non-bolting respectively, or into five subgroups with different traits based on 29 morphological traits. Principal coordinate analysis based on eight bulb related traits divided all accessions into 6 groups. Yield among the accessions ranged from 1.60 to 16.78 t/ha, and three accessions yielded above 15 t/ha. Pearson analysis suggested bulb yield was significantly positively correlated with bulb weight (r = 0.99), bulb diameter (r = 0.73), bulb height (r = 0.53), clove number (r = 0.52), leaf width (r = 0.52). Allicin content ranged from 0.81 to 3.01 %. Pseudostem diameter was found to be significantly positively correlated with allicin content but with the low correlation coefficient (r = 0.23). The result will obviously be helpful for breeder and researchers to comprehensively understand the genetic background of the collection and more easily select the target accessions, especially those with high yield and allicin content.     

柚类种质资源表型多样性分析及综合评价

为了建立合理的柚类分类系统并为柚类育种提供参考,本研究以82份柚类种质资源为试材,采用变异系数、Shannon-Weaver多样性指数、方差、相关性、主成分、聚类、回归分析等对其26个表型性状进行多样性分析、差异分析及综合评价。结果表明:这82个品种的26个性状的变异系数为0.26%。其中翼叶面积和果心面积变异较大,其他性状遗传特性较稳定;单果重、果横径、果形指数、果皮厚、囊瓣数、种子数、果心长和宽、叶片长和宽、叶片面积、花瓣宽、花柄长等性状等级分布均匀,翼叶面积、花瓣数、雄蕊长分级较少且分布不均;来源于中国大陆以外品种的果皮厚、叶柄长、翼叶长,明显优于长江流域和珠江流域来源的材料,但雌蕊长则相反;选育品种的叶片长、宽和面积显著大于遗传材料和地方品种;82个品种可聚为大翼叶大果型、大翼叶小果型,小翼叶大果型,小翼叶小果型4个类群;前7个主成分累计贡献率75.57%,包含了柚类表型性状的大部分信息;26个性状F平均值0.45,其中早暹柚得分最高为0.69,红肉琯溪蜜柚最低为0.24;囊瓣数、种子数等12个性状与F值极显著相关;回归方程筛选出单果重、囊瓣数等19个性状。本研究说明柚类种质资源具有较高的表型多样性,筛选出的19个性状可作为柚类综合评价指标,为柚类育种提供科学依据。