The effectiveness of using a minituber crop for selection of agronomic characters in potato breeding programmes

Summary Performance of 20 potato genotypes was studied for seven agronomic characters in crops raised from minitubers and normal seed tubers. Correlation coefficients were computed between minituber crop and normal seed crop in order to study the selection efficiency at minituber crop level. The performance of normal seed crop was significantly better than the minituber crop for various characters including tuber yield and its components. Correlation coefficients between minituber and normal seed crop were significant for various characters except number of stems and number of tubers. Highest correlation coefficient (r=0.86) was for tuber yield followed by average tuber weight (r=0.67) and number of nodes (r=0.63). The results suggest that selection for tuber yield can be practised at the minituber crop level in potato breeding programmes     

Analyzing genotype by environment interaction in potato using yield-stability index

The plant breeding program of the National University of Colombia carried out 10 potato regional trials during 1998 and 1999 to evaluate 15 promising potato clones (Solanum tuberosum ssp.andigena). Genotype by environment interaction was analyzed using Kang’s methodology, which links yield performance and phenotypic stability. A MACRO was implemented using the SAS system to obtain yield-stability indices. Shukla’s variance was estimated by restricted maximum likelihood (REML), which allowed handling unbalanced data for both genotypes and replicates. In addition, a multivariate analysis methodology was developed, based on the yield-stability index. This methodology is useful when tuber yield is categorized by size and quality, which is usual in Colombian potato harvests.     

马铃薯杂种群体的性状相关及其配合力分析

本试验以7个优良马铃薯品种(系)按不完全双列杂交设计配制组合,分析了群体主要性状与生产力的遗传相关及其配合力效应.结果表明,群体平均单株结薯数、平均块茎重、商品薯数量和产量及小薯数量和产量与群体产量的遗传相关达显著或极显著.平均块茎重、商品薯数量和产量是筛选商品价值较高的优良群体的重要相关性状.亲本的一般配合力效应在平均单株结薯数、平均决茎重、商品薯产量、小薯产量和数量几个性状上对模型Ⅰ差异显著,组合间的特殊配合力效应均达到显著差异.特殊配合力方差为总方差的61.47%～147.52%,表明该群体的生产力主要由非加性基因控制.相对配合力总效应值与产量的相关达极显著水平(r_(3.4)=0.99).综合评定亲本801-5,Katahdin和Baraka在马铃薯群体和品种选育中具有较高的利用价值.     

马铃薯主要数量性状遗传参数及通径分析

本试验对14个品种(系)的23个数量性状的遗传力、遗传变异系数以及诸性状与单株产量的相关系数进行了估算,对产量、株高(x_1)、块茎数(x_2)和单块茎重(x_3)散了通径分析。结果表明,该3个性状决定了产量变异的98.67％,而剩余通径系数仅为0.1153,说明该3个性状是影响产量的主要因素。     

Selection of Yield-Associated Morphological and Biochemical Traits Using Correlation and Path Coefficient Analysis in Potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) in the Foothills of North-Western Himalayas

The objective of the study was to assess the direct and indirect effects of 13 important morphological and biochemical traits on yield enhancement in 28 advanced breeding lines of potato (Solanum tuberosum L.) in the foothills of north-western Himalayas. Tuber yield was positively correlated with number of tubers per plant (r?=?0.76), number of stems per plant (r?=?0.53), number of leaves per plant (r?=?0.43) and tuber weight (r?=?0.37). Furthermore, tuber yield exhibited a significant negative correlation with days to maturity (r?=???0.39). Days to 50% emergence had a significant negative correlation with protein content (r?=???0.42). Path analysis revealed that the components of yield, number of tubers per plant and tuber weight, had high positive direct effects (0.876 and 0.618, respectively) on tuber yield, whereas the effects of other traits were low (≤?0.128). Furthermore, tuber weight had an indirect negative effect on tuber yield through the number of tubers. Tuber size had a low correlation (0.19) with tuber yield because a positive indirect effect (0.451) through tuber weight was balanced by a negative indirect effect (??0.254) through tuber number. The number of stems and number of leaves had positive indirect effects (0.377 and 0.377, respectively) on tuber yield through tuber numbers, whereas days to maturity had a negative indirect effect (??0.298) through tuber numbers. There were virtually no indirect effects through the biochemical traits. The implications for potato breeding are discussed.     

Genetic variation in the response of andigena potatoes to inorganic fertilizers

Summary Tuber yield, dry matter and true protein content were studied in 24 andigena potato genotypes. Their performance and response differed greatly and significantly when grown at three levels of inorganic N, P and K fertilizer application. In general, tuber yield and protein content increased with increased fertilizer level, whereas dry matter content initially decreased but then increased significantly with fertilizer additions. For all three characteristics, genotype x fertilizer interaction was significant, and although there was a wide genetic variability for relative responsiveness of different genotypes, no significant undesirable association was detected for performance. The genotypes JEX/A 674, 706 and 744 are most promising and could be used for wide-scale cultivation and for breeding.     

马铃薯品种淀粉含量和淀粉产量的表现及其稳定性分析

淀粉加工在马铃薯产业中起着重要作用。然而,目前广泛种植的原料薯仍然是淀粉含量不高的菜用薯。为选出适于黑龙江垦区种植的淀粉加工型马铃薯品种,试验采用随机区组设计,以‘延薯4号’为对照,对5个品种(‘同薯29号’、‘克新27号’、‘东农310’、‘内-9’和‘希森5号’)的块茎产量、淀粉含量以及淀粉产量进行评价,并进行稳定性分析。对照品种‘延薯4号’产量达46300 kg/hm^2,淀粉含量13.76%,淀粉产量6394 kg/hm^2,均表现出较好的稳定性。‘克新27号’产量(41731 kg/hm^2)低于‘延薯4号’,但淀粉含量(18.94%)高于‘延薯4号’,结果淀粉产量(7976 kg/hm^2)最高,但表现并不稳定。‘东农310’和‘希森5号’淀粉含量分别为18.33%和20.46%,并具有较高的淀粉产量,分别为6709和6658 kg/hm^2,表现稳定。该研究为淀粉企业正确选择品种提供了基础数据。     

Sequential Path Analysis of Yield Components in Potato

In order to determine proper selection criteria for tuber yield in potato clones obtained from true potato seed (TPS) and to evaluate relationships between tuber yield and its components, an investigation was conducted using the five check cultivars Agria, Marfona, Draga, Agata, and Arinda, and 120 potato clones obtained from TPS. The study was conducted in an augmented randomized complete block design with three replications. Yield and its components were recorded. Correlation coefficient analysis showed that tuber yield had significant positive associations with number of tubers per plant, average weight per tuber (tuber size), plant height, diameter of main stem, and number of main and secondary stems per plant, whereas its correlation with tuber dry-matter concentration was significantly negative. Number of tubers per plant, tuber size, and plant height had significant standardized partial regression coefficients with very small tolerance and large variance inflation factor (VIF) values. These were considered as the first-order variables in sequential path analysis.     

Heritability of Yield Components Under Irrigated and Drought Conditions in Andigenum Potatoes

Drought is one of the major abiotic factors that affect potato production in the tropics and sub-tropics. Molecular plant breeding offers promising opportunities for developing drought tolerant cultivars, but genetic gains to be achieved through breeding depends strongly on the genetic variance and heritability of traits used in the selection process. In the present study, genetic variance and heritability of tuber yield and its components were estimated in the native potato cultivar group Andigenum, expected to include promising drought tolerant progenitors. Twenty-seven full sib families obtained from crossing 18 parents arranged in 3 mating sets were grown under irrigated and terminal drought conditions. Heritability for tuber yield, estimated from female to male variance components was 0.68 and 0.41, respectively, in the irrigated treatment, and only 0.18 and 0.06 under drought conditions. Tuber number was highly significantly correlated to tuber yield but the heritability of this trait (estimated both from female to male variance) was lower than yield heritability and its non-additive genetic variance was higher than its additive genetic variance, particularly when estimated from the female variance component. Heritability of average weight per tuber estimated for male variance component was very high under both irrigated and drought conditions. Its additive genetic variance was much higher than its non-additive genetic variance. However, average weight per tuber correlated to tuber yield within parents but not within families. These results indicate that selection for increased tuber yield under drought conditions in the Andigenum cultivar group may be slow due to its low heritability and high value of non-additive genetic variance. They also suggest that yield components may not be useful as indirect selection criterion for yield, because of their low heritability and/or poor association with yield. The identification of drought tolerance related traits with high heritability and closely associated to tuber yield under drought is consequently required to improve adaptation of potato to drought-prone conditions and efficient utilization of Andigenum potatoes for this purpose.     

Tuber yields and specific gravities inSolanum tuberosum populations recurrently selected for resistance to potato leafhopper

Solanum tuberosum genotypes from the 3rd, 5th, and 7th generations of recurrent selection for resistance to potato leafhopper were compared with genotypes from the base, unselected population for tuber yield and specific gravity over a five year period. Mean tuber yields of the genotypes in the 3rd and 5th generations were equal to the yield of those in the base population. The mean tuber yield in the 7th generation was significantly lower than the mean in the base population and the means in the other selection generations. However, the mean tuber specific gravities of the 5th and 7th generation genotypes were slightly higher than the mean in the base population. The variability of tuber yield among genotypes in the 7th selection generation was lower than the variability in the base population and in the 3rd and 5th selection generations. It was concluded that there was moderate genetic potential for selecting genotypes with resistance to potato leafhopper that had acceptable tuber yields in the 3rd and 5th selection generations, but by the 7th generation the potential was considerably lower. The genetic potential for selecting resistant genotypes with acceptable tuber specific gravities remained about the same in each of the selection generations.     

Somaclonal variation in tuber traits of potato

Summary About 13,000 somaclones of 17 cultivars and clones of potato were obtained from in vitro callus cultures and individually planted in a greenhouse, followed by tuber generations grown in the field. These plants were subjected to the multistage selection procedure commonly used in potato breeding. Over a period of five years and three field generations the tuber number, size, shape, eye depth, starch content, starch yield and tuber appearance of these somaclones were assessed and compared with that of the controls. These characters varied depending on donor genotype and trait. The frequency of variants was assessed and there were acceptable proportions of desirable abberrants and invariants among the somaclones. Depending on trait the average gain rate for all donor genotypes ranged between 0.2 and 2.3% for-deviants, between 12.2 and 15.5% for invariants and between 0.1–1.4% for +deviants. It is concluded that this technique should be used into potato breeding programmes to improve commercially important characteristics of specific cultivars and breeding clones.     

植物生长调节剂对马铃薯脱毒试管薯形成的效应研究

利用 3个品种 5种植物生长调节剂采用多因素多重复试验设计 ,分析了基因型、植物生长调节剂对马铃薯脱毒试管薯形成的影响。方差分析表明 :对于试管薯单瓶块茎数和单瓶块茎重量 ,基因型、植物生长调节剂的影响达显著水平 ,基因型与植物生长调节剂的互作不明显。试管薯单个块茎重量的变异系数在基因型间、植物生长调节剂间差异很大     

Selection of monoploids for protoplast fusion and generation of intermonoploid somatic hybrids of potato

The union of potato monoploid genotypes (2n=1x =12) through protoplast fusion may result in vigorous somatic hybrids due to a reduction of the “genetic load” normally present in this highly heterozygous tetraploid (2n=4x=48) crop. More than 100 androgenic monoploids derived from diploid (2n=2x=24)Solanum phureja Juz. & Buk. andS. chacoense Bitt. xS. phureja clones were evaluated in field trials during 1996 and 1997 to identify the most promising genotypes for protoplast fusion experiments. Compared to the total population, the 1996 selected genotypes had higher means for tuber number (30.1 vs 11.2 tubers/plant), average tuber weight (3.0 vs 1.8 g/tuber) and total yield (66.1 vs 20.4 g/plant). Similarly, the 1997 selected genotypes had higher means for tuber number (42.8 vs 25.4 tubers/plant), average tuber weight (3.6 vs 2.5 g/tuber) and total yield (114.0 vs 63.4 g/plant) compared to the total population. The 31 selected monoploid genotypes from 1996-97 varied in their response to protoplast isolation and culture from no growth (9), cell enlargement (5), limited cellular divisions (8), callus formation (5) to plant regeneration from callus (4). Chemical fusion and electrofusion produced three groups of intermonoploid somatic hybrids. Polymorphic simple sequence repeat (SSR) loci enabled distinction of somatic hybrids from parental somaclones. Rapid DNA extraction with SSR analysis enabled screening of calluses to identify somatic hybrid tissue prior to plant regeneration. The somatic hybrids were highly polyploid, mostly hexaploid (2n=6x=72), possibly due to fusion of endopolyploid protoplasts and/or chromosomal doubling during plant regeneration.     

马铃薯原种的种植密度对植株性状、产量性状和经济参数的影响

为了探讨马铃薯原种在小垄栽培(垄距70 cm)条件下的适宜种植密度,利用马铃薯品种荷兰15号脱毒原原种为试验材料,种植并生产原种一代。采用单因素随机区组设计,设株距10 cm、15 cm、20 cm、25 cm和30 cm共5个处理,采用通径分析探讨了植株性状对产量的影响,运用方差分析探讨了密度与植株性状(株高、主茎数和茎粗)、产量性状(单株结薯数、平均薯块重、单株产量、产种量、繁殖系数、公顷产量)和经济参数(产投比和经济效益)的关系。研究结果表明:株距在10~30 cm之间时,如果株高越高、主茎数越多,那么产量就越高;随着株距的增大,单株结薯数逐渐增多,单株产量逐渐增高,繁殖系数和产投比逐渐增大,主茎数和产种量无显著变化;垄株距为70×30 cm的处理产量最高,繁殖系数最大,产投比最高和经济效益最好,是小垄稀植栽培的适宜密度。     

Genotypic stability analysis of eight potato varieties tested in a series of ten trials

Genotypic stability analyses were carried out for five characteristics of eight potato varieties which had been tested in the New Brunswick Variety Trial in the past ten years, 1961–1970. Special attention was paid to three economic traits, i.e., marketable yield, specific gravity and dry matter yield. General adaptability was defined in this paper as having average genotypic stability and above-average mean performance. Kennebec showed the best general adaptability of marketable yield, Hunter for specific gravity and Netted Gem dry matter yield. No variety was ranked at the top for both marketable tuber yield and specific gravity. Some implications of this study on potato breeding are discussed.     

晋西南山区川水地马铃薯不同栽培密度试验

对晋西南山区川水地覆膜种植的马铃薯主栽品种费乌瑞它进行不同栽培密度试验。试验结果的方差分析表明:每公顷密度在53 892～89 820株范围内,其单株商品薯数、单株薯重、单株商品薯重、小区产量、小区商品薯产量存在显著与极显著差异;单株结薯数无显著差异;小区产量以每公顷76 989株最高,小区商品薯产量以每公顷67 365株最高,而在生产实际中,追求更多的是商品薯产量,所以,该区域的马铃薯品种费乌瑞它覆膜种植以每公顷67 365株的密度为宜。     

Progeny mean, heterosis and heterobeltiosis inSolanum tuberosum x tuberosum andS. tuberosum x andigena families under a short day sub-tropic environment

Summary Solanum tuberosum x tuberosum (TxT) families were compared withS. tuberosum x andigena (TxA) families as progeny mean, heterosis and heterobeltiosis for ten important agronomic characters by evaluating 72 cross combinations (36 of TxT and 36 of TxA, from 18 common female parents), for three successive seedling and clonal generations under short day sub-tropic conditions. TxA families had more vigorous progenies, higher tuber yield, higher number of tubers, larger tubers and better general impression than TxT families. The TxA families were inferior to the TxT families for characters such as tuber colour and uniformity of tuber colour, but their progeny means were within the acceptable range. High progeny means of TxA families were associated with high heterosis and high heterobeltiosis in these families, although there were a few exceptions. High mean performance for tuber yield and tuber number were associated with high variance of these traits in TxA families. It is concluded that, unlike under long day environments, andigena adapted to short days can be used advantageously for exploiting heterosis in the potato breeding programmes of short day subtropic environments.     

马铃薯品种块茎性状的遗传分析

对Mira等 10个马铃薯品种的 2 2个杂交组合无性一代的块茎产量等 8个块茎性状的群体遗传参数和配合力效应进行了试验研究 ,结果表明 :淀粉含量的遗传受母本加性效应和亲本间非加性效应控制 ;单个块茎重的遗传受父本加性效应的控制 ;皮色、结薯数和块茎产量的遗传受非加性效应控制 ;薯形、肉色和块茎外观的加性和非加性效应同等重要。两个亲本 (至少有一个 )的一般配合力高的杂交组合后代的群体表现优于双亲具有一般配合力平均值的杂交组合 ;而双亲具有一般配合力平均值的杂交组合的群体表现优于双亲一般配合力都很低的杂交组合。根据一般配合力选择亲本配制大量杂交组合 ,并从中筛选优良单株和优良TPS组合的方法非常适合于马铃薯育种     

Genetic improvement effects on yield stability in durum wheat genotypes grown in Italy

In durum wheat (Triticum durum Desf.) the improvement of yield stability represents an important component for agricultural progress worldwide. This work reports on the evaluation of the yield performance of 65 durum wheat genotypes (landraces, old and new cultivars with different years of release and advanced breeding lines), in a range of Italian environments to assess the changes in adaptation and yield stability achieved over the last century as results of the genetic improvement. The Additive Main effect and Multiplicative Interaction (AMMI) analysis was used to capture a large portion of the Genotype × Environment interaction (GE) sum of squares and to separate main and interaction effects. The breeding strategies adopted during the last decades have contributed to reduce the interaction of genotypes with environments selecting genotypes with better stability across a wide range of locations and years and modern genotypes outperformed the old ones in all test environments with a strong adaptability to improved fertility. The old cultivars were characterized by a minimal responsiveness to improved environmental conditions, showing an almost stable nominal yield in agreement with the concept of “biological” or “static” stability. In contrast, the modern cultivars were highly responsive to fertility improvements and showed a pronounced adaptation to high-input environments. Notably, within the group of modern cultivars two of them, Tiziana and Giusto, showed a high-yield stability in biological terms and a high nominal yield across the tested environments. Giusto and Tiziana were the best cultivars in terms of both nominal yield and minimal GE interaction, indicating that selecting for improved yield potential may increase yield in a wide range of environments.     

马铃薯稻草覆盖免耕栽培与传统栽培比较研究

为探索马铃薯稻草免耕栽培增产机理,我们开展了马铃薯稻草覆盖免耕栽培与传统栽培比较研究。结果表明,与传统栽培相比,稻草覆盖免耕栽培马铃薯薯皮光滑,块茎大小整齐,出苗率高,株高和叶片数较多,中、后期植株生长速度明显加快。分枝数多、单株块茎重和大薯率高是马铃薯稻草覆盖免耕栽培增产的主要原因。