Runner formation on strawberry plants in autumn and winter

Summary The present experiments with runner plants of the strawberry variety Deutsch Evern are part of an investigation carried out to determine the conditions under which runners are produced in autumn and winter. This information is necessary to produce runners on mother plants of strawberry selections which are tested for viruses during these seasons.In this paper the influence of increasing the light intensity during the day or the intensity of the additional light, or both, on runner production under a 16 hr day was studied at 17°, 20° and 23°C.It was found that at 20° and 23°C more runners were produced by increasing the light intensity during the day or the intensity of the additional light, or both. But increasing the light intensity produced the best results at 23°C. At that temperature there was a decline in runner production in December and January, if only the light intensity during the day or the intensity of the additional light had been increased. This was hardly the case when both light intensities had been increased.     

北部冬麦区冬小麦越冬冻害时空变化特征

利用我国北部冬麦区43个气象站点1951—2014年气象资料,综合考虑越冬期最大降温幅度、极端最低气温、负积温、平均气温、降水和风速等冬小麦越冬冻害致灾因子,采用主成分法构建冬小麦冻害指数(FII),FII值越大,冬小麦遭受冻害越严重。结合历史冻害灾情资料,验证冻害指数在研究区域的适应性。采用M-K方法分析冬小麦冻害的突变特征,探究北部冬麦区越冬冻害的时空分布特征。结果表明,FII能较好地反映北部冬麦区冬小麦冻害情况。近60年北部冬麦区冬小麦冻害指数的年际变化均呈显著下降趋势。1980年前后冻害指数发生突变,气候变暖后我国北部冬麦区冬小麦冻害发生的频率、程度和范围明显减少;而由于气候变化的不稳定性增加,自2000年以来,冬小麦中度到重度冻害有所增加。冻害指数的空间分布总体呈现随着纬度和海拔高度的增加而加重的趋势。燕太山麓平原副区遭受冻害最为严重,黄土高原沟壑副区和晋冀山地盆地副区遭受冻害较轻。     

Vegetative propagation of selected lettuce plants in autumn and winter

Summary A method is described of propagating lettuce (Lactuca sativa L.) by cuttings, reducing losses of selected heads to a minimum. This method is successfully applied to heads selected under glass in autumn and winter.Three ways of propagation by cuttings are dealt with, viz. by head cuttings, shoot cuttings and leaf cuttings.     

Runner formation on strawberry plants in autumn and winter

Summary In order to test strawberry selections for viruses, for which runners are necessary, the second writer tried, in connection with experiments carried out by Borthwick and Parker (1), to produce runners in the autumn and winter of 1952–53 by interrupting the dark period, however, without any result. Experiments carried out in 1953–54 have shown that too low a temperature was the cause of this failure, for runner formation in autumn and winter is dependent not only on day length but also on temperature.In the course of our 1953–54 experiments we found that in 1937 Darrow (2) had already made mention of the interrelation of temperature and day length in runner formation. However, it is not likely that sufficient runner formation would have taken place, had we applied his findings.     

秸秆还田结合秋覆膜对旱地冬小麦耗水特性和产量的影响

秸秆还田和秋覆膜是西北旱地雨养农业区冬小麦生产中有效的节水增产措施。为明确西北半干旱雨养农业区不同作物秸秆还田结合秋覆膜种植模式下冬小麦田土壤蓄水保墒和节水增产效果,于2011年9月至2013年6月连续2个小麦生长季在甘肃省通渭县进行了田间定位试验,比较玉米秸秆还田结合秋覆膜、单一玉米秸秆还田、麦秸秆还田结合秋覆膜、单一麦秸秆还田和传统平作种植对西北旱地冬小麦耗水特性和籽粒产量的影响。结果表明,与传统平作相比,冬小麦全生育期秸秆还田结合秋覆膜处理0～200 cm平均土壤贮水量在2011—2012和2012—2013年度分别提高6.1%和9.6%,而单一秸秆还田分别提高0.7%和4.6%。在降水偏多的2011—2012年度,除玉米秸秆还田结合秋覆膜处理冬小麦全生育期0～200 cm土壤贮水消耗量比传统平作低19.0 mm (P0.05)外,其余各处理无显著差异;在降水偏少的2012—2013年度,秸秆还田及秸秆还田结合秋覆膜处理平均比传统平作多耗水39.1 mm,其中,两个秸秆还田结合秋覆膜处理显著增加冬小麦返青至拔节阶段的耗水量,显著降低开花至成熟阶段耗水量,并增加了对深层土壤水分的调用。与传统平作相比,秸秆还田结合秋覆膜处理可使小麦籽粒产量提高31.0%～69.4%,水分利用效率提高25.6%～43.0%;而单一秸秆还田的小麦籽粒产量提高1.2%～28.0%,水分利用效率提高3.0%～11.6%。以玉米秸秆还田结合秋覆膜处理增产效果最好,2年平均籽粒产量和水分利用效率分别较传统平作提高51.1%和41.7%,且显著高于其他处理。因此,玉米秸秆还田结合秋覆膜种植模式能显著提高冬小麦籽粒产量和水分利用效率,适宜在西北旱农区小麦生产中应用。     

Response of four winter wheat cultivars to triallate

Summary Genetic variation among four winter wheat cultivars for response to treatment with triallate was examined. The cultivars showed differential tolerance based on stand count, however, differential tolerance was not seen for any of the other traits examined including visual score, and the mature plant traits, tiller count and yield. Significant effects due to increasing the rate of chemical were observed. An increase in yield was seen at the 0.5 and 1.0 kg/ha rates of triallate. This yield increase was paralleled by trends toward increasing seed number/head and tiller number/unit area. The results indicate that the effect of triallate on wheat has two components. The first component, toxicity, is seen on all cultivars, but the extent of damage varies significantly among cultivars. The second component is positive and leads to an increase in yield without interacting significantly with genotype.     

Agronomic and quality effects in winter wheat of a gene conditioning resistance to wheat streak mosaic virus

Wheat streak mosaic virus (WSMV) is one of the most important diseases limiting winter wheat (Triticum aestivum L.) production in the western Great Plains of North America. There is no known effective WSMV resistance within the primary gene pool of wheat. However, a resistance gene (Wsm1) has been transferred to wheat from a perennial relative, intermediate wheat-grass [Thinopyrum intermedium (Host) Barkworth & DR Dewey]. Nebraska-adapted winter wheat lines carrying Wsm1 were used to characterize the effects of this alien introgression on agronomic and quality traits. Sister-lines from six breeding populations were evaluated under virus-free conditions, and under a naturally occurring viral infection. In uninfected locations, no significant difference for grain yield was detected between resistant (R) and susceptible (S) lines, when averaged over populations, but resistant lines had significantly higher test weights. Within populations, significantly higher grain yield was observed only in population 1, while significantly higher test weights occurred in populations 1, 2, 5 and 6. At the infected location, resistant lines were significantly higher in yield in five of six populations. In two of six populations, susceptible lines were significantly higher in bread loaf volume and bake mix time, while in the remaining populations, no significant quality differences were observed. As the Wsm1 gene provided yield advantages under viral infection, and there was no yield detriment in the absence of the virus, its deployment in hard winter wheat cultivars merits consideration.Joint contribution of the United States Department of Agriculture, Agricultural Research Service and the Department of Agronomy, University of Nebraska-Lincoln as Journal Series Paper No. 15066. Mention of firm names or trade products does not imply that they are endorsed or recommended by the USDA or the University of Nebraska over other firms or products not mentioned.     

Use of AFRCWHEAT2 to predict the development of main stem and tillers in winter triticale and winter wheat in North East Germany

Winter triticale (cv. Grado) and winter wheat (cv. Taras) were grown in Rostock, Germany (54.2°N) for 5 years (1985–91) each with up to four sowing dates. Shoot apex development of the main stem and the two most developed tillers was observed by sampling eight plants every 3–10 days. The developmental submodel of the AFRCWHEAT2 simulation model was tested to predict the developmental events: emergence, start of floral initiation, double ridge, start of floret initiation, end of spikelet initiation and anthesis.Anthesis of main shoots was observed 8 days earlier for triticale than for wheat which was explained by an earlier start of reproductive development in triticale than in wheat. Variation in the dates of phenological events was greater for floral initiation and double ridges than for floret initiation and anthesis in both cereals. Dates of the early stages of development varied more in triticale than in wheat and more for main shoots than for tillers. For both species, standard deviations of the differences between observed and model predicted dates of phenological events were larger among developmental stages than between cultivars. Prediction of the early stages of development (floral initiation and double ridge) was poor for both species. The beginning of floret initiation and anthesis were simulated more accurately. We suggest that progress in simulating the development of cereals is more limited by lack of knowledge about plant physiology, rather than by the process of modelling. Better quantification of the vernalization requirements of different species is identified as an important topic for future work. Developmental parameters calculated for main shoots could also be used to closely predict the development rates of tillers. Differences between the development rates of main shoots and tillers were explained by the weather conditions each tiller group experienced and not by differences in their physiological responses to climatic factors. More research is needed to describe differences in development and vernalization requirements of a tiller when compared with that of a main shoot.     

Genetics of androgenesis in winter and spring wheat genotypes

Androgenetic response and its inheritance was studied in nine winter type and two spring type wheat genotypes by crossing them in line × tester fashion. The 18 F₁ and 11 parental genotypes were raised in completely randomized block design with three replications and subjected to anther culture. Data were recorded with respect to per cent calli induction, percent regeneration and per cent green plant development. Analysis of variance revealed considerable genetic variation for all the three component traits of androgenesis. Both additive and non-additive genetic variances were involved in the androgenetic response with the preponderance of non-additive gene action in case of calli induction and additive gene action for regeneration and green plant development. Low estimates of heritability (narrow sense) for calli induction and moderate for regeneration and green plantlet development were obtained. The genotypes, Henies VII, Pnfjoumee, Saptdhara, Sentry, Purthi of winter wheat and HPW147 of spring wheat were identified as good general combiners for almost all the androgenetic parameters and have potential use in future haploidy breeding programmes. This revised version was published online in July 2006 with corrections to the Cover Date.     

我国北部冬麦区小麦区域试验重复次数和试点数量的优化设计

农作物品种区域试验重复次数和试点数量的合理配置有利于提高试验的成本效率和品种选择效率。本研究分析了2010—2019年期间北部冬麦区小麦品种区域试验的重复次数和试点数量设置的合理性,依据小麦品种试验的信噪比和遗传力水平随重复次数和试点数量的变化规律,提出了重复次数和试点数量的优化设计方案。结果表明:(1)北部冬麦区小麦单点试验的遗传力平均达到0.87,需要的重复次数平均值仅为1.4,说明3次重复可以充分保证试验精确度的需求。(2)北部冬麦区水地组和旱地组小麦区域试验达到0.75的遗传力水平时,需要的试点数量分别为11个和13个,目前有效试点数量分别约为11个和8个,分别达到0.75和0.60的遗传力水平。(3)小麦品种区域试验结果对品种的审定和应用十分重要,而每年都可能有少数试验点因为各种异常情况而报废,为保证试验结果的可靠性,可按H=0.75的水平需求安排试验点数量和重复次数,即重复次数可保持当前的3次;水地组的试点数量可保持在11个左右;旱地组可将试点增加到13个;如要将遗传力提高到0.80的水平,则需约16个试点。     

Response to selection, combining ability and heritability of coleoptile length in winter wheat

Selection of winter wheat cultivars with long coleoptiles is an important component of improving emergence, weed suppression and grain yield in low rainfall regions of the world. Seven winter wheat cultivars were hybridized in a Griffing’s half-diallel mating design, method 2 (reciprocals excluded, parents included), model 1 (fixed), and the progeny analyzed for coleoptile length in the F₁ through F₄ for response to selection, general combining ability (GCA), specific combining ability (SCA) and heritability. Highly significant differences existed for GCA among progeny in each generation. SCA was highly significant in the F₁, F₂ and F₄, although SCA estimates were inconsistent among generations in each progeny population. The SCA/GCA ratio was 0.15, 0.11, 0.06 and 0.04 in the F₁ through the F₄, respectively, indicating that additive effects increased with homozygosity. Broad-sense heritability for coleoptile length was estimated at 0.86, 0.76, 0.60 and 0.78 for the F₁ through the F₄, respectively. Realized heritabilities ranged from −0.16 to 0.85 with a mean of 0.32 in the F₃ and ranged from −0.68 to 0.68 with a mean of 0.13 in the F₄. Spearman’s rank correlation coefficients (R_S) were significant for all generation comparisons except the F₁:F₂, indicating that changes in rank for coleoptile length were insignificant. Cultivars with long coleoptiles and high GCA were the best parents for improving coleoptile length. Sustained selection over generations for coleoptile length was more effective than one generation of selection for genotypes both with and without reduced height genes.     

庆阳市冬小麦育种的回顾与设想

庆阳位于甘肃省东部,是该省冬小麦的主产区之一.本区气候干旱、寒冷,病虫等自然灾害频繁,小麦产量低而不稳、效益差.选育高产、稳产、优质的旱地小麦品种,是生产上的迫切需要.陇东学院农学系育成的"庆选"、"庆丰"、"西峰"三大系列品种的大面积推广,为本区旱地小麦生产做出了很大贡献.     

江苏冬小麦在新疆春麦区示范种植研究

2012年将扬麦16、扬麦13、扬麦11等3个江苏冬小麦春性品种,按照新疆昭苏县春小麦的栽培管理方式示范种植,虽然遇到了严重春旱的影响,3个品种仍表现了较好的适应性,其平均单产仍高于对照春小麦品种。对其子粒抽样检测表明：扬麦16和扬麦13的粗蛋白质（干基）及湿面筋（14%湿基）含量均高于对照春小麦品种,且也比在江苏种植提高;而对照春小麦品种的沉淀值（14%湿基）、面团形成时间及稳定时间高于冬小麦,说明这3个冬小麦品种首次在新疆高海拔、高寒地带的春麦区示范种植成功。     

Characterization of the durable resistance to yellow rust in old winter wheat cultivars in the Netherlands

Summary Winter wheat cultivars released in the Netherlands before 1930 carried durable resistance to yellow rust. Cultivars released in the period between 1930 and 1950 often were durably resistant while recent cultivars infrequently showed durable resistance. This durable resistance was not difficult to transfer to new cultivars. Twenty nine older cultivars with durable resistance and eight recent non-durably resistant cultivars were tested in the seedling stage and in the adult plant stage against 12 West-European yellow rust races and against some non-European races in the seedling stage only. The adult plant tests were carried out in race nursery tests in the Flevopolder. Per race nursery all 37 cultivars, planted in hills of about 20 plants on both sides of the highly susceptible cv. Michigan Amber, were exposed to one race.The infection type of each cultivar-race combination was scored on 0 to 9 scale once in the seedling stage and twice in the adult plant stage. In the race nurseries the percentage leaf area affected was evaluated three times to be used to calculate the area under the disease progress curve (AUDPC). This AUDPC multiplied with the mean infection type in the field gave the susceptibility index (SI).The infection types were classified into resistant (R), intermediate (I) or susceptible (S) when the infection types were 0 to 3, 4 to 6 or 7 to 9, respectively. Four categories of resistance were discerned on the basis of the three infection type scores: 1) RRR, overall resistance; complete or near-complete resistant at all stages. 2) SRR, adult plant resistance, complete- or near-complete resistant at the adult plant stage only. 3) SRS and SSR, temperature sensitive resistance, the resistance changed from the one evaluation data to the other. 4) SSS and an SI lower than that of Michigan Amber, partial resistance.The frequencies of overall, adult plant and temperature sensitive resistance were 1.4, 52 and 54% in the older cultivars and 40, 62 and 22% in the recent ones, respectively. Among the older cultivars all had a fair to high level of partial resistance, the SI being on average only 20% of that of Michigan Amber, while most cultivars also seemed to carry temperature sensitive resistance. The partial resistance of the recent cultivars was of a much lower level with a mean SI compared to that of Michigan Amber of 61%. Partial resistance was highly correlated (r = –0.94) with the mean resistance scores from the Dutch Recommended Cultivars Lists. It was concluded that partial resistance and temperature sensitive resistance were the major components of the durable resistance in the older cultivars.     

Height,competition and yield potential in winter wheat

Summary A monogenic dominant male sterility is used for hybrid production in autumn and winter cauliflower. The ratio of male sterile plants in the backcross progenies of autumn cauliflower was 1:1 over five years (1987–1991). However, a significant deficit of male sterile plants was observed in the winter type over the same period.The influence of the temperature on the male sterile phenotype was studied within backcross progenies planted inside polythene tunnels. Six classes of phenotype were defined during the flowering period (from May to November). At low temperature, some male sterile plants developed partial to complete male fertility, whereas at high temperature, male fertile plants became male sterile.Segregation among the progenies of self-pollinated unstable male sterile plants did not deviate from the expected 3:1 ratio. Plants homozygous for the male sterility allele have been revealed by test crosses with a male fertile plant.For use in seed production, stable male sterile plants are vegetatively maintained; however, crossing lines isogenic except at the MS locus would allow male sterile plants to be raised from seed.     

Relative genetic contributions of ancestral genotypes to Yugoslavian winter wheat cultivars

Summary Pedigrees of 142 Yugoslavian winter wheat cultivars were traced to 110 ancestral genotypes, of which 41 contributed significantly. In each of the four major Yugoslavian wheat breeding programs, the most important ancestor, as evaluated by mean coefficient of parentage, was Akagomughi, source of the genes Rht8 and Ppd1. The other 13–19 ancestors accounting for the majority of the remaining germplasm, varied considerably among institutions. The relative contributions of ancestors changed little between the periods 1967–76 and 1982–86, with the exception of Neuzucht (source of a 1B/1R translocation), which became much more important in the latter period.     

Molecular mapping of partial resistance to powdery mildew in winter wheat cultivar Folke

The Swedish winter wheat (Triticum aestivum L.) cultivar Folke has a long record of partial and race non-specific resistance to powdery mildew (caused by Blumeria graminis f. sp. tritici) in the field. The aim of the present study was to map the main genetic factors behind the partial resistance in Folke and identify molecular markers for use in marker-assisted selection. A population of 130 recombinant inbred lines was developed from a cross between Folke and the moderately susceptible spring wheat line T2038. The population was tested for powdery mildew resistance over two years at two locations in Norway and genotyped with DArT and SSR markers. Composite interval mapping detected a total of eight quantitative trait loci (QTL) for powdery mildew resistance; six with resistance from Folke on 2BS, 2DL, 5AL, 5BS and 6BS and two with resistance from T2038 on 5BS and 7AL. None of the loci with resistance from Folke mapped to chromosomal regions with known race-specific resistance genes, which confirmed the race non-specific nature of the resistance in this cultivar. The molecular markers linked to the reported QTL will be useful as a tool for selecting partial and potentially durable resistance to powdery mildew based on the resistance in Folke.     

Development of winter wheat with excellent resistance to pre-harvest sprouting and rain damage

Pre-harvest sprouting and high alpha-amylase activity are the most serious problems for the wheat production in Hokkaido, the northern most part of Japan. It has become more frequent for wheats to be exposed to continuous rain for several days in harvest time. In addition, low temperature below 15 ^°C, combined with rainfall, accelerates the damage of pre-harvest sprouting. Therefore, we started a breeding program in 1998 to develop wheat varieties with excellent resistant to sprouting damage in Hokkaido.Selection and evaluation of pre-harvest sprouting of resistant lines were conducted by two tests. One test was artificial rain treatment of intact spikes and the other was a germination test of hand-threshed grains at 10, 15 and 20 ^°C. The spikes of each line and variety were collected at physiological maturity and at one week after the first sampling date. Falling number was also measured.We have succeeded in breeding a deeply dormant breeding line, Kitakei 1802, from 1,923 doubled haploid lines raised by anther culture from the cross between Kitakei 1616 and Nishikazekomugi. Kitakei 1802 hardly sprouted through 10 days” continuous rainfall treatment at low temperature (15 ^°C) and maintained high falling number (> 300 s) in 2002 and 2003.