杂交中稻再生力的鉴定方法

2002－2003年分别以25个和18个杂交中籼迟熟组合为材料,从头季稻与再生力密切相关的若干性状中选择了可操作性强的5个性状进行与再生稻产量间的定量研究,提出了根据头季稻（前期）“分蘖力”、（中期）齐穗期“单位颖花茎鞘干物重占有量”和（后期）头季稻收后第5日头季稻桩再生芽的“出鞘率”3个性状,将杂交中稻再生力分     

川南冬水田区杂交中稻蓄留再生稻的品种比较

以13个杂交中稻品种为材料,比较了品种间头季稻与再生稻产量及其穗粒结构.结果表明,品种间头季稻、再生稻及两季总产的差异显著,头季稻高产品种有野香优3306、川康优673,产量在600 kg/667 m2以上;再生稻高产品种为内6优丝苗、绵优7353、川康优787和宜香优2115,产量超过200 kg/667 m2;两季...     

杂交中稻再生力与头季稻农艺性状的相关性研究

为探明杂交中稻再生力与头季稻农艺性状的关系，给强再生力品种（组合）的选择提供依据，选用229个杂交组合，经3次试验，再生力与头季稻性状的相关及通径分析表明，⑴能体现碳水化合物遗留量的成熟期单茎茎鞘干重，对再生力的直接效应最大或接近最大，两者呈极显著正相关，且其回归方程具较好的预测功能，故可将茎鞘干重作为衡量杂交中稻组合再生力的重要指标。⑵对群体生态环境影响较大的穴有效穗数，与再生力的简单负相关均不显著，偏相关却均极显著，直接效应亦较大，显示其是影响再生力的重要性状。⑶与再生力呈负相关的株高、剑叶长度、穗着粒数、穗实粒重、成熟期以及呈正相关的分蘖力，3次试验的效应均不一致，说明它们对再生力的影响不够稳定。     

再生稻高产种质资源筛选及高产群体分析

再生稻高产种质资源是选育强再生力水稻品种的物质基础,缺乏具有强再生力的水稻品种是制约再生稻发展的重要因素之一。引进247份早抽穗水稻核心种质在江汉平原作再生稻种植,从中筛选高产再生稻种质资源,并探究高产再生稻产量形成的关键因素,为再生稻种质资源创新及新品种选育提供基础材料和理论依据。结果表明,247份核心种质在江汉平原两季稻均能正常抽穗成熟,各农艺性状变异系数在10.31%~51.83%,从中筛选出27份高产水稻种质资源。其中,4份双季高产种质两季总单株产量均超过60.00g,可作为亲本用于水稻再生力基因挖掘和再生稻高产育种。再生稻高产群体产量构成分析表明,提高再生稻产量的关键是提高其每穗颖花数和有效穗数;再生稻高产种质头季稻产量与再生季稻产量呈极显著负相关,表明再生稻高产育种方向应从追求单季高产转变为追求周年高产。     

再生稻种植产量差形成的研究

为明确安徽省沿江地区再生稻种植产量差形成的原因,筛选出该地区适宜的再生稻种植品种,以9个杂交水稻品种为试材,比较分析了其头季和再生季生育期、再生力、产量及其构成因素等性状。结果表明,在产量构成因素中,造成不同品种头季稻产量差异的主要因素是单位面积上的有效穗数;导致再生季产量差异的主要因素是单位面积上有效穗数和每穗着粒数。准两优608再生季单产5.27 t/hm~2,2季综合产量高达13.59 t/hm~2,可作为该地区再生稻种植的优选品种;皖稻119和新两优6号头季产量高,再生力较强,再生季产量潜力大,可以作为该地区再生稻种植的候选品种。研究表明,生产中可通过增加单位面积上有效穗数,主攻大穗,并在维持较高结实率的基础上提高千粒质量以实现再生季产量增加和获得2季综合高产。     

湖南双季稻区杂交中稻最佳播期初探

对汕优63等4个杂交中稻组合进行分期播种期试验,其结果表明：株高与播种期为二次曲线相关;颖花数与播种期呈负相关,单位面积产量与播种期用多项式逼近法模拟为一双峰曲线,以4月10日播种为最高点,5月28日播种为次高点。同时,对杂交稻组合的最佳播种期及湖南双季稻区杂交中稻高产最佳播种期进行了讨论,提出了4月10日是湖南双季稻区部分杂交中稻组合高产最佳播种期,5月28日为优质高产兼顾的最佳播种期。     

杂交中稻施用赤霉素“双增”技术

利用杂交中稻培育再生稻是一种费省效宏的稻田种植制度,自1986年在四川省大面积推广以来,已取得了巨大的社会、经济效益。由于再生稻生育期短,再生芽的萌发及生长在很大程度上要依赖于头季稻母茎的养分贮藏,为了再生稻的稳产、高产,必须要种好头季稻,尤其是头季稻后期的生长发育。而赤霉素具有延长叶片功能期,提高光合强度,打破休眠,促进萌发等功效,如何把它应用于杂交中稻,使之     

川东南高温伏旱区杂交中稻品种库源结构对稻米整精米率与垩白粒率的影响

以25个杂交中稻组合为材料,研究了品种齐穗期库源结构对稻米整精米率与垩白粒率的影响。结果表明：整精米率与源库比呈极显著负相关,垩白粒率与源库比呈显著或极显著正相关。其原因在于,随着杂交组合每穗着粒数的增加,单位颖花的源占有量减少,稻穗籽粒灌浆速率降低,灌浆历期延长,籽粒容重增大,整精米率提高;当籽粒灌浆     

再生稻高产栽培技术讲座：第二讲 再生稻高产栽培技术

再生稻高产的基础是种与头季稻中稻-再生稻这种制度的发展,要以两季高产稳产为目标。必须种好头季稻,不仅因为两季高产头季是关键,而且因为再生稻的生育是头季稻的延续,要使再生稻高产,必须以种好头季稻为基础。这里不去全面分析头季稻高产的原理与技术,面仅仅就与再生稻密切相关的几个方面加以讨论。     

浅谈杂交中稻的再生利用

简述了杂交中稻再生利用的发展概况及发展前景，充分利用光、热、水、土、肥资源，提出了选用再生力强的高产品种。高产稳产途径为地膜育秧适期早播，做到头季避开伏旱，再生季躲过低温，保证两季高产；施好促芽肥，保证休眠芽成活与早生快发；高留稻桩，保留倒二、三节蘖芽再生利用。     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.     

Distribution,ecology and reproductive biology of wild tomatoes and related nightshades from the Atacama Desert region of northern Chile

Over the past 20 years, several expeditions were made to northern Chile to collect populations of wild tomatoes (Solanum chilense, S. peruvianum) and allied nightshades (S. lycopersicoides, S. sitiens), and obtain information about their geographic distribution, ecology and reproductive biology. Restricted mainly to drainages of the Andean and the coastal cordillera, populations are geographically fragmented. The two nightshade species are rare and threatened by human activities. Adaptation to extreme aridity and soil salinity are evident in S. chilense and S. sitiens (the latter exhibits several xerophytic traits not seen in the tomatoes) and to low temperatures in S. lycopersicoides and S. chilense. All tested accessions are self-incompatible, with the exception of one S. peruvianum population collected at the southern limit of its distribution. Several distinguishing reproductive traits—anther color, attachment, and dehiscence, pollen size, and flower scent—suggest S. sitiens and S. lycopersicoides attract different pollinators than S. chilense and S. peruvianum. The four Solanum spp. native or endemic to Chile provide a variety of novel traits which, through hybridization and introgression with cultivated tomato, could facilitate development of improved varieties, as well as research on a variety of basic topics, including plant-pollinator interactions, abiotic stress responses, and evolution of reproductive barriers.     

The exploration of genetic resources of Portuguese cabbage and kale for resistance to several Brassica diseases

Summary Twenty three accessions of nine Portuguese cabbage and kale land races from different geographic origins were tested at the seedling stage for resistance to several important brassica diseases. Resistance to downy mildew (Peronospora parasitica), expressed as necrosis of the cotyledon mesophyll, was found in all the accessions. Type A resistance to cabbage yellows (Fusarium oxysporum f. sp. conglutinans race 1) was present in most of the landraces. Resistance to clubroot (Plasmodiophora brassicae race 6) was found in one accession of the Portuguese tree kale. High resistance to blackleg (Leptosphaeria maculans) and white rust (Albuco candida) was not detected, although several accessions showed 20 to 30% of plants with intermediate expression of resistance. All Portuguese cole accessions were susceptible to blackrot (Xanthomonas campestris pv. campestris).     

Production and characterization of intergeneric diploid cybrids derived from symmetric fusion between Microcitrus papuana Swingle and sour orange (Citrus aurantium)

Plants were regenerated from intergeneric somatic hybridization between embryogenic protoplasts of Microcitrus papuana Swingle and leaf-derived protoplasts of sour orange (Citrus aurantium L.) via electrofusion. The regenerated plants were morphologically similar to the leaf parent in growth vigor, leaf and branch structure. FCM analysis showed that they were diploids. Simple-sequence-repeat (SSR) and cleaved-amplified-polymorphic-sequence(CAPS) were employed for hybridity characterization. SSR banding patterns of the regenerated plants were identical to the leaf parent, sour orange, indicating that they possessed nuclear component derived from sour orange. DNA amplification with chloroplast and mitochondrial universal primers, followed by restriction endonuclease digestion, revealed polymorphism between the fusion parents. Therefore, this method was used to determine the cytoplasmic compositions of the regenerated plants. Banding patterns for all the polymorphic primer/enzyme combinations of the regenerated plants were similar to those of the embryogenic parent, M. papuana, suggesting that only the cytoplasmic components derived from the embryogenic parent were present in the regenerated plants. FCM, SSR and CAPS demonstrated that intergeneric diploid cybrids have been successfully obtained by symmetric fusion. Related results concerning nuclear and cytoplasmic composition of previous diploid somatic hybrids and potential mechanism for regeneration of such kind of plants are discussed herein. This revised version was published online in July 2006 with corrections to the Cover Date.     

Breeding barriers between the cultivated strawberry, Fragaria × ananassa, and related wild germplasm

Five-hundred interspecific and intergeneric crosses were performed among accessions of the wild strawberries Fragaria vesca(2x), Duchesnea indica (8x), Potentilla tucumanensis (2x) and 9 genotypes of the cultivated strawberry, Fragaria×ananassa (8x), following an incomplete diallele mating design. Crosses between D. indica and F.×ananassa produced many putative hybrids when D. indica was used as female but a few achenes and plants when used as male; therefore, pollen-pistil compatibility relations were analyzed by fluorescence microscopy in this direction of the cross. Of the genotypic combinations, 78.6% were incompatible at the stigma level and 17.2% at the first third of the style. Only 3.6% were pollen-pistil compatible and produced fruits with achenes (seven did not germinate or originated short-lived plants and nine produced normal plants). F.vesca×F.×ananassa crosses produced 35 hybrid achenes but only 14% germinated, yielding short-lived plants; histological analyses revealed that inviable seeds had less developed (or collapsed) endosperms and smaller embryos than control plump F. vesca seeds. P.tucumanensis was only used as male, with negative results. These species and genera are partially isolated by a complex system of pre- and post-zygotic barriers. Knowledge of their nature would allow the breeder to devise strategies to put the genetic variability available in the group into a useful form. This revised version was published online in July 2006 with corrections to the Cover Date.