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1.
This study was conducted to determine effects and interactions of plant density on digestibility and plant morphology of diverse orchardgrass ( Dactylis glomerata L.) clones. Propagules of ten orchardgrass clones with contrasting morphology from two maturity groups (inflorescence emergence differed by 8d) were evaluated in sward (0·15-m centres) and spaced (0·60-m centres) plantings. Plants were harvested from spring growth on a common date near anthesis and from summer growth when about 5 weeks of forage growth had accumulated. The plants were separated into morphological parts before measuring their size and in vitro digestible dry matter (IVDDM). There were few plant density × orchardgrass clone interactions, and correlation coefficients of clones grown at the two plant densities generally were high (e.g. 0·87 in spring and 0·67 in summer for IVDDM of total herbage). Plant density had little effect on morphology of leaf blades from reproductive tillers, but leaf blades of vegetative tillers were 12% (spring) and 22% (summer) longer from sward than from spaced plantings. Moreover, reproductive tillers were 26% taller in sward than in spaced plantings. Also, leaf blades of vegetative tillers in spring growth were more than twice as long, of similar width and 65% thicker than leaf blades from reproductive tillers. Because divergent genotypes respond similarly to plant density, it is concluded that observations taken in spaced plantings of orchardgrass can be used to make inferences about relative differences in sward plantings for the traits studied. 相似文献
2.
Naveen Garg 《Journal of Crop Improvement》2017,31(6):801-815
Assessment of genetic variability in available germplasm, identification of genetically diverse genotypes for developing F1 hybrids, and to generate further variability are prerequisites for any crop improvement program. Here, 15 accessions, including 5 released varieties, of round gourd were used to estimate genetic variability for 6 qualitative and 9 quantitative traits. Most accessions had round, shining, and light green fruits. Degree of secondary lobing of leaf blade was the most diverse qualitative trait. The 15 accessions were grouped into four clusters, of which two were solitary. Cluster II had eight accessions, followed by cluster I with five accessions. The grouping pattern revealed that geographical diversity might or might not be correlated with genetic diversity. The principal component analysis indicated that the first three components accounted for 85.73% of the total variation, with principal component 1 (PC1) accounting for 37.21%, PC2 for 36.35%, and PC3 for 12.16% of the total variation. Of nine traits studied, early yield contributed 55.24% toward genetic divergence, followed by vine length (21.90%) and number of primary branches per vine (14.29%). The highest broad-sense heritability (95.60%) and genetic advance (123.06%) were recorded by early yield followed by vine length and number of primary branches. Crossing between genotypes belonging to clusters I, III, and IV with those belonging to cluster II, and between clusters I and III has been advocated to develop F1 hybrids, and to search for transgressive segregants with new combinations of genes to bring necessary improvement in the crop. 相似文献
3.
S. C. Ferrari Usandizaga E. A. Brugnoli A. I. Weiss A. L. Zilli M. Schedler E. M. Pagano E. J. Martínez C. A. Acuña 《Grass and Forage Science》2015,70(4):695-704
Acroceras macrum is a warm‐season grass used for pastures, and it has high nutritive value. The scarce genetic and reproductive information about this grass is limiting its breeding for forage. The objective of this research was to determine the number of genotypes and cytotypes present in a collection established in Argentina, and to estimate the diversity of this species based on molecular markers, and morphological and agronomic characteristics. The number of genotypes among forty‐seven accessions was determined using ISSR markers. The identified genotypes were further characterized for ploidy levels. In addition, the genetic distances among them were estimated with ISSR markers. They were also propagated and planted into the field following a randomized complete block design with four replications, and a group of sixteen morphological and agronomic variables were evaluated. A total of twenty‐seven genotypes were identified in this collection; twenty‐two genotypes were tetraploid (2n = 4x = 36) and five were hexaploid (2n = 6x = 54). These two cytotypes were found clearly separated by both genetic and phenotypic characteristics. Above‐ground biomass, internode length, initial growth and number of spikelets per inflorescence were the most variable traits. The high diversity present in this collection will allow for the initiation of a breeding programme for A. macrum. 相似文献
4.
Leymus chinensis is an economically and ecologically important grass that is widely distributed across eastern areas of the Eurasian steppe. A better knowledge of genetic diversity of L. chinensis could be valuable in the efficient utilization, conservation and management of germplasm collections. Genetic diversity in thirty‐seven morphological characters of 293 accessions was assessed in three successive years. Based on these qualitative and quantitative characters, the genetic diversity indices (Shannon indices) of traits and geographical populations were estimated, and a principal coordinates analysis and a path analysis were undertaken. Compared with the yellow‐green type of L. chinensis, the grey‐green type had significantly (P < 0·05) more genetic diversity. In addition, the path analysis suggested that the combined effects of genetic diversity and vegetative traits could explain 0·206 of the total variance in plant reproductive traits. The highest Shannon genetic diversity index of accessions (H = 2·252) was observed in accessions from the region of longitude of 124–128°E, suggesting the most abundant germplasm of L. chinensis in this region. 相似文献
5.
利用数理统计软件对12份橡胶草种质材料的主要农艺性状进行相关性、遗传多样性及聚类分析。结果表明：12份橡胶草种质主要农艺性状存在较大差异,其中叶片长、叶片宽、叶形指数、叶柄长变异系数均较大,Shannon-weaver多样性指数H′在1.86～1.99,具有丰富的多样性;叶片长、叶缘类型与其它性状之间相关性较大,其中叶片长与叶片宽、叶形指数、叶柄长及叶缘类型均呈显著正相关;叶缘类型与叶片长、叶片宽、叶柄长均呈显著正相关,与叶脉颜色呈极显著负相关;通过聚类分析将12份材料划分为3个类群,综合评价发现,Ⅱ类群的3份材料(206-1、208-1、214-1)表现显著优于Ⅰ和Ⅲ类群,可作为橡胶草育种的优选材料。 相似文献
6.
为有效评价和利用广西斑茅种质资源,扩增甘蔗遗传基础。对183份广西斑茅种质资源主要表型性状及遗传多样性进行分析。结果表明：广西斑茅种质资源表型遗传多样性比较低,13个描述型性状的遗传多样性指数在0.0000~1.2349之间,平均为0.3070,以毛群较高,生长带形状较低,空心、气根、根点排列和脱叶性4个性状无多态性表现;不同地区的斑茅资源遗传多样性指数在0.2851~0.5072之间,且以钦州的多样性最大,其次是桂林和崇左,以来宾的多样性最小。5个数值型性状的变异系数在13.54%~29.11%之间,平均为19.59%,以叶宽比较大,叶长较小;10个地区的斑茅资源变异系数在16.48%~21.92%之间,以桂林最大,百色最小。通过聚类分析,183份资源可以分为10个类群,各类群遗传分化不明显,与地理来源无密切联系。本研究揭示了广西不同地区斑茅的表型特异性和遗传多样性,为斑茅资源的采集、保育和杂交利用提供理论参考。 相似文献
7.
The effect of forage removal on the growth of five winter and five spring triticale genotypes was studied in 1992 and 1993 in field experiments in north-eastern Spain. When cut, winter triticales produced more biomass and leaf area than spring types owing to their higher tillering capacity. The leaf area index (LAI) at anthesis was similar in both groups in both clipped and uncut plots, but spring triticales had a greater leaf area on the main stem than winter types. Winter types had a greater leaf area on the tillers than spring types. Spring and winter types had a similar physiological response to forage removal, except for modifications in flag leaf area. In spring types triticale flag leaf area was reduced by clipping, whereas in winter types flag leaf area was increased. Forage removal resulted in less dry-matter accumulation in all plant parts, maximum weight of the plant being reduced by about 20% and the rate of growth by around 13%. LAI at anthesis decreased by 37% as a result of clipping, and the leaf area duration from anthesis to maturity decreased by 36%. The duration of growth increased after clipping. Heading, anthesis and maturity dates were delayed by clipping, but grain filling duration was not affected. 相似文献
8.
《Field Crops Research》1987,17(2):163-173
The relative sensitivity to water stress at different growth stages of goosegrass (Eleusine indica (L.) Gaertner) was investigated by measuring water status and growth of groups of plants stressed during the vegetative stage, the reproductive stage, and during both stages. Plants were grown from seed in large pots in a controlled-environment chamber at 29/23°C and 14-h photoperiod. In all treatments, decreasing leaf water-potential was correlated with decreasing osmotic and pressure potentials. Plants stressed during the flowering stage maintained greater pressure potentials at any leaf water-potential than plants stressed during vegetative growth or stressed twice. Prestressing the plants did not induce lower leaf osmotic potentials at full turgor. However, dehydration was the main cause of low osmotic potentials measured in the leaves of the plants stressed twice. Stomatal closure occurred over a relatively large range of leaf water-potentials. The sensitivity of stomata to water stress in this species was fairly similar in the two growth stages studied. Leaves of plants stressed during the flowering stage had a smaller decline in total biomass during the stress period, and a higher rate of growth after rewatering, compared to the plants that received a stress during vegetative growth and flowering or were stressed during vegetative growth. 相似文献
9.
以129份株型多样性丰富的莲属（Nelumbo Adans.）群体为供试群体,观测与株型相关的立叶高度、花柄高度、立叶短径、立叶长径等数量性状。供试荷花群体株型性状变异丰富,立叶高度、花柄高度变异系数分别达39.68%和41.69%,立叶短径、立叶长径变异系数分别为29.70%和31.41%。选用多态性好的98对SSR引物对129份莲属种质进行多位点扫描。利用STRUCTURE V2.2软件对供试莲属品种进行基于混合模型的群体结构分析。利用GLM模型分析与莲株型性状相关联的SSR标记。结果表明：从群体结构看,供试群体最终可被划分为4个亚群,中国莲传统品种和中美杂交种属于不同的亚群,同时有部分遗传背景复杂的杂交种在不同亚群间分布。通过关联分析共找到11个标记与花柄高度、立叶高度、立叶长径、立叶短径等4个性状显著相关。其中,SSR067、SSR132、SSR458标记与所观测株型性状均显著相关,可能由于基因连锁或者一因多效引起。在连续2年的重复试验中,SSR132和SSR458标记均可与立叶长径、立叶短径相关联,表明这2个标记可能受环境影响较小。 相似文献
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11.
Spatial analysis of genetic diversity in a comprehensive collection of the native grass Bromus auleticus Trinius (ex Nees) in Uruguay 
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下载免费PDF全文 Bromus auleticus Trinius (ex Nees) is a perennial allogamous C3 grass native to the Campos grasslands. It has potential to play a key role in restoration of both abandoned agricultural and overgrazed lands. We aim to reveal the existence of local adaptation and to assess whether phenotypes could be differentiated in relation to their ecogeographic region of origin. Previous reports estimated significant levels of variability among and within populations, but as yet there is no evidence of local adaptation and phenotypic relations with ecogeographic regions for this species. Indeed, there is a lack of knowledge about the spatial distribution of diversity, which limits the possibilities of using B. auleticus in ecological restoration and plant breeding. A comprehensive collection of 82 accessions of B. auleticus from eight ecogeographic regions within Uruguay was used to characterize diversity by measuring phenologic, morphologic, productive and reproductive traits. We found high diversity among B. auleticus accessions, and the spatial distribution of this diversity follows a pattern accounted by ecogeographic regions to a large extent. Our results also indicate large genotype × environment interaction, confirming local adaptation. Phenotypic values permitted, with a 3.7% error rate, discrimination of accessions according to their ecogeographic region of origin, suggesting the existence of differentiated ecotypes. We consider that the diversity observed should be conserved and used for breeding cultivars of this species and for the restoration of degraded grasslands by considering ecogeographic regions when selecting seed sources. 相似文献
12.
Inter simple sequence repeat(ISSR) polymorphism was used to determine genetic diversity and phylogenetic relationships in 90 genotypes of wild and cultivated species of Oryza from different geographical regions of the world. In all the 17 primers used in ISSR-PCR, a total of 11 464 bands were amplified at 253 band positions/loci. The primer UBC-809 amplified the maximum bands(1 059) at 21 band positions. UBC-810 and UBC-835 amplified the minimum of 391 bands each at 7 and 14 band positions, respectively. The mean polymorphism information content ranged from 0.44 to 0.84 and resolving power ranged from 8.69 to 23.53. Un-weighted pair group method with arithmetic mean dendrogram and population structure based on the 17 primers separated all genotypes into 4 major clusters with a genetic similarity of 53%–100%. The first two clusters consisted of 30 O. rufipogon accessions each. In the third cluster, O. nivara and O. longistaminata grouped as one sub-cluster and all other O. nivara accessions and cultivars grouped as another sub-cluster. The fourth cluster had only five O. rufipogon accessions which can be a source of new genes. Four sub-populations were identified within O. rufipogon and two sub-populations within O. nivara at K = 7. A subset of six primers with high resolving power values were the most informative and grouped all genotypes almost similarly as the 17 primers did. Use of these six highly informative primers in ISSR-PCR is a cost effective and robust method for assessing genetic diversity in large germplasm collections of wild rice species. 相似文献
13.
A. S. Laidlaw 《Grass and Forage Science》2005,60(2):200-209
The relative contribution of tillers present in April and those appearing in consecutive periods in spring was assessed for perennial ryegrass cultivars in the three maturity groups (early, intermediate‐ and late‐heading). Each group was represented by two diploid and one tetraploid cultivar each in plots in their third (2000) and fourth (2001) harvest years in three replicated blocks receiving an average of 325 kg N ha?1 and cut seven (in 2001) or eight (in 2000) times annually. ‘Main’ tillers and their daughters were marked with colour‐coded PVC‐covered wire loops in early April as were daughters which appeared in consecutive periods between harvests, the loop colour identifying the period of origin of the tiller. Tillers were harvested at cutting height (5 cm) before the plots were harvested and the herbage from tillers with the same colour code bulked per plot. Tillers were identified retrospectively as ‘reproductive’ if they had been decapitated at the previous harvest. Dry‐matter yield was higher in the early than late‐heading cultivars in April and early May but this was reversed in harvests in late May and June. The early heading group had a lower lamina content than the late‐heading group during reproduction growth, both due to the reproductive tillers (mainly those which overwintered) having a lower leaf content and to their being fewer and smaller vegetative tillers during the reproductive phase than for the late‐heading group. Turnover of tillers was high in spring due to decapitation of reproductive tillers and rapid post‐flowering tillering. This was particularly pronounced in the early heading group which also had slightly more tillers marked in April which were subsequently decapitated than in the other maturity groups, i.e. 0·56 compared with 0·44 for the late‐maturing group. Mean ratios of rate of death: rate of tillering for 3 years (1999–2001) for the early and late‐heading groups were 0·8 and 0·4, respectively, for April–May and 1·1 and 2·4, respectively, for June indicating the different patterns in tiller turnover for the two extreme maturity groups. Information on tiller origin and contribution to yield can be used to refine tiller‐based grass growth models. 相似文献
14.
Sulaiman Cheabu Peerapon Moung-Ngam Siwaret Arikit Apichart Vanavichit Chanate Malumpong 《水稻科学》2018,25(4):218-226
Seed-setting rate, yield components and grain quality traits of 169 accessions from an exotic rice germplasm were tested under high temperatures from 40 °C to 45 °C for 6 h during the daytime at the vegetative and reproductive stages, respectively. The results showed that heat stress significantly decreased the seed-setting rate of all the accessions, but the heat stress effects varied among accessions. Based on the decreases in seed-setting rate at high temperatures, N22 was the most tolerant, followed by AUS17, M9962, SONALEE and AUS16. Moreover, the reductions in seed-setting rate and yield under heat stress were more serious at the vegetative stage (45 d before heading) than at the booting stage (15 d before heading). In addition, heat stress also affected grain quality, especially by conferring chalkiness to most of the accessions, but SONALEE did not change much. The heat-tolerant accessions identified here and the phenotype protocols developed could be used in future genetic studies and breeding programmes focused on heat tolerance. 相似文献
15.
为了更好地利用甘蓝型油菜资源,以引进的124份和青海省20份甘蓝型油菜资源为材料,利用50K SNP芯片分析了这些资源的遗传多样性,并在春油菜环境下鉴定了开花期、茎秆强度、产量和品质等13个相关性状.结果表明:资源两两之间的遗传距离平均为0.4683,遗传距离大于等于0.5的资源对数占总对数的36.45％,表明这批资源... 相似文献
16.
《Field Crops Research》2006,95(2-3):327-335
Nepal has a wide diversity of rice landraces in all rice-growing areas from low to high altitude. A baseline survey in Jumla, a high-altitude site (2200–3000 m), identified rice landraces with different names that differed in phenotype and were adapted to the extreme high-altitude environment. Jumli Marshi was the most common traditional rice variety, accounting for 85% of samples collected. The genetic diversity of these landraces was assessed by agro-morphological variability and microsatellite marker polymorphism. Forty-two qualitative and quantitative traits and 39 microsatellite (simple sequence repeats, SSR) markers were assessed among accessions with 10 different names. The accessions showed low morphological diversity with an average Shannon Weaver diversity index of 0.23. Only 16 morphological traits showed significant variation among the accessions. Discriminant function analysis showed that only 36% of accessions could be clustered according to name by morphological traits. Only one SSR locus was polymorphic, distinguishing only one accession. The names used by farmers to describe the phenotypic characteristics of panicle and grains were inconsistent indicators of genetic identity. We conclude that the Jumla landrace population has a narrow genetic base. The diversity detected was sufficiently low for it to be possible that there was a single origin for all of the Jumla landraces. 相似文献
17.
一种水稻营养生长期快速出叶基因型的发现及初步分析 总被引：1，自引：0，他引：1
通过对14个水稻品种分期播种试验,发现在籼稻品种盐恢559中存在一种营养生长期快速出叶基因型。将盐恢559与出叶速率最慢的Lemont进行比较,两者在各播期的播始历期均相近的情况下,前者的主茎叶片数始终比后者多4～5张,出叶速率极显著快于后者,且出叶速率差异主要表现在秧田期和大田营养生长期,幼穗分化期两品种的出叶速率差异不显著。分析盐恢559、Lemont及其配制的2个回交群体及F2群体的单株出叶速率,推测盐恢559的快速出叶性状为多基因控制的数量性状,其中可能存在效应较大的数量基因。通过对双亲及回交后代群体中部分类型亚群体性状调查发现,这种基因型出叶速率快,单株茎蘖数、茎蘖增加速度以及高峰苗均相对较高,单株有效穗数、每穗粒数明显高于出叶速率慢的类型。讨论了对这种快速出叶基因型进行深入研究的必要性及育种应用的可能性。 相似文献
18.
《Plant Production Science》2013,16(3):268-275
AbstractJilin Province is a major spring maize area of China with the highest regional yield. Nevertheless, a large yield gap existed between actual and potential yield. A super-high yield (> 15 t ha–1) is needed to fulfil the increasing demand. However, yield has been limited due to the lack of knowledge on crop performance in relation to super-high yielding managements. Ten field experiments in Jilin Province from 2008 to 2011 were summarized to understand the growing process of high-yielding spring maize. Plants were categorized into high yield (HY) plants which had a yield > 12 t ha–1, medium yield (MY) plants which had a yield of 9 – 12 t ha–1, and low yield (LY) plants which had a yield < 9 t ha–1. Crop growth during vegetative stages showed no significant differences among yield categories. HY plants grew faster than LY and MY plants after the twelvecollar stage, and the difference became more and more pronounced during silking to 30 days after silking, and even afterwards. Moreover, HY plants had a shorter vegetative period than either LY or MY plants without impacts in vegetative growth, and longer reproductive period, which contributed to better kernel formation and filling. HY plants also had the capacity to maintain a high leaf area index (LAI) at 30 days after silking, which provided for a continuous dry matter accumulation during and after this period and thus resulted in a super-high yield. Hence, special attention should be paid during the 30 days after silking in order to maintain a high photosynthetic capacity and achieve a super-high yield. 相似文献
19.
为明确蓖麻种质资源的遗传多样性和群体遗传结构,利用SSR分子标记结合PopGene1.32软件、MEGA7.0软件和Structure2.3.4软件等,对来源于国内5个地区(16个省市)和国外3个国家的191份蓖麻种质进行遗传多样性和群体遗传结构分析.结果表明:86对SSR引物共检测出194个等位变异,其中平均等位基因... 相似文献
20.
为了解广西乐业野生春兰种质间的亲缘关系,提高其利用效率,对66份春兰种质资源的43个表型性状（13个数量性状和30个质量性状）进行多样性和相关性分析,对乐业县各来源的春兰资源进行聚类分析,并从表型性状主成分分析的基础上对其进行综合评价。结果表明：春兰种质表型多样性丰富。数量性状变异程度较高,变异系数（CV）为11.62%~41.56%,其中花梗长的CV值最高。质量性状变异系数为9.26%~55.7%,以开花习性、唇瓣主色和花瓣形状的CV值居高。说明花梗长、开花习性、唇瓣主色和瓣形都是春兰观赏性状的重点选育方向。相关性分析结果表明,花侧萼片宽（SSW）和花中萼片宽（SMW)、花侧萼片长（SSL）和花中萼片长（MSL）、花侧萼片形状（SSS）和花中萼片形状（MSS）、花瓣内侧主色（PIMC）和花萼片主色（SMC）之间呈显著正相关,相关系数分别为0.7951、0.7648、0.771、0.741;花侧萼片夹角（SSA）和侧萼片先端形状（SSPS）、唇瓣形状（LS）和中萼片先端形状（SSPS）、唇瓣色斑数量（LSN）和叶色（LC）之间则呈显著负相关,相关系数分别是-0.4557、-0.4316、-0.4181。数量性状和质量性状主成分分析分别提取5个和11个主成分,共10个因子,累计贡献率分别为78.193%和73.023%,可反映乐业春兰的总体形态表现;聚类分析结果显示,在欧氏距离为18.77处可将66份春兰种质划分为4组,其中第Ⅰ组只有一个55号品种,第Ⅱ组包含9个品种,主要以来源地相同为主,第Ⅲ组28份种质以红色花为主,第Ⅳ组28份种质,主要特征是花朵较大。研究筛选出19138-38、19138-40、18011、18007、19134-1共5份种质综合评价较高。该结果为了解广西野生春兰种质间亲缘关系及其评价与利用提供理论依据。 相似文献