暖冬条件下播期对不同类型小麦幼穗分化的影响

对3个不同类型小麦品种在不同播期下的幼穗分化进程及受冻情况进行了系统观察和研究。结果表明,在气候变暖,秋、冬温度较高的情况下,小麦幼穗分化进入各时期的时间早晚为强春性品种>春性品种>半冬性品种;播期对小麦幼穗分化的伸长期、单棱期和二棱期持续时间长短影响较大;在早播的情况下。春性越强的小麦品种,越冬前幼穗分化发育速度越快,达到的发育阶段越高,越冬期间越容易被冻死。据此,提出在河南气候变暖,秋、冬温度较高的情况下,首先在生产上要选用半冬性品种,适当搭配晚播早熟的春性品种;其次,无论半冬性品种或春性品种。播种期都不宜过早。     

冬麦春播小麦穗分化阶段对低温胁迫的响应及耐寒性

以长江中下游地区引进的10个冬小麦品种为材料,在忻定盆地春播条件下,于2013-2014年研究了低温胁迫对冬小麦穗分化阶段光合作用、渗透调节物质及膜系统产生的影响,并对其抗寒性能进行综合评价.结果表明:在低温胁迫下,不同品种小麦叶片的离子渗漏率、可溶性糖和可溶性蛋白质含量均不同程度地升高,总叶绿素含量明显下降.通过主成分分析和抗寒性度量值(D值)排序,不同品种冬小麦幼穗分化期间的抗寒性为:渝麦10、扬麦20、云麦42的抗寒性较差;扬麦13、渝麦12、宁麦13的抗寒性较强且年际稳定性好,D值分别为0.665 ～0.659、0.493～0.495、0.471 ～0.583;而作为对照的宁2038、新春30分别为0.368～0.397、0.328～0.330.扬麦13、渝麦12、宁麦13的两年籽粒产量显著高于其他品种,可作为忻定盆地的引种材料.     

玉米杂种与亲本穗分化期功能叶基因差异表达与杂种优势

为探讨玉米杂种优势的分子机理,以10个玉米自交系及其组配的38个杂交种为材料,利用cDNA-AFLP技术,分析杂种与亲本在玉米雌穗小穗分化期功能叶片的基因差异表达类型与主要农艺性状的杂种表现及杂种优势的关系。研究表明：（1）杂种的基因相对于其双亲,存在质和量的表达差异,其中质的差异表达类型包括：单亲沉默表达,双亲沉默表达,亲本显性表达和杂种特异表达等类型。（2）在雌穗小穗分化期,同一差异表达类型中不同杂交组合间差异很大;从总体平均看,杂种特异表达类型占25.22%,亲本显性表达类型占21.46%,双亲沉默表达类型占8.27%,单亲沉默表达类型占33.49%。（3）单亲沉默表达与株高的杂种表现呈显著正相关;双亲沉默表达与穗粗的杂种优势呈显著负相关,显性表达与行粒数和单株粒重的杂种优势呈显著负相关,其余表达类型与所有农艺性状杂种表现及杂种优势均不相关,并对结果进行了讨论。     

一种非光敏特早熟小麦品种光温特性之初探

以强冬性小麦品种京冬8号为对照,采用分期播种试验,分析了非光敏特早熟小麦新品种冬早5号的生长发育进程和光温特性,并探讨了播期对两种小麦品种生育期和产量的影响.结果表明,冬早5号小麦品种比对照品种京冬8号早熟3～4 d,标准播期增产43.4%.冬早5号小麦品种在低温、短光照条件下也能完成正常的穗分化进程,其每经历一个穗分化期Z所用的天文日照时数、有效积温和光温积明显少于京冬8号.该品种在穗分化阶段对光照不敏感,无需经过严格的春化阶段和光照阶段,品种类型介于冬性和春性之间,冬前适播期较广,适合秋播也可以春播,这在小麦育种领域是个突破.     

小麦不同品种和播期对发育阶段的效应

以热时间（thermal time)为尺度研究了小麦不同品种和播期对发育阶段的效应,结果表明,小麦分蘖发生的早晚以生态因子调控为主,基因型差异较小;分薛- 节期为冬性品种（京411）一生中可变性最大的生育阶段,穗分化进入单棱斯的早晚以基因型效应为主,生态因子的影响次之,单棱－二棱期为春化作用的敏感期,冬性品种晚播（3月2日）春化效应可延迟到小花原基分化期之前,小麦物候期与穗发育阶段的对应关系具有一定的可变性,冬性品种较强的春化作用增加了其生态可变叶原基数;春化过程结束前,物候发育及穗发育阶段累计GDD与相应生殖器官原基分化的数的相关性不明显,春性品种（扬麦158）的物候发育及药隔分化期之前的穗发育阶段与各类顶端原基的分化数均具有极显著的正相关关系。     

陕西关中地区杂种小麦强优势组合优势型研究

选用在陕西关中地区表现优良且某一农艺性状表现突出的11个冬小麦品种(系),根据农艺性状分为大粒型、多穗型、穗重型和中间型4类,组成6种NCII杂交组合模式,研究不同组合模式的杂种优势,探讨根据农艺性状划分杂种小麦亲本优势型在杂种小麦强优势组合选配中的应用.结果表明:在所组配的6种组合模式中,以大粒×多穗型组合模式表现突出,其杂种优势、超亲优势和超标优势均明显高于其它组合,分别达到了59.9%、37.1%和22.5%,因此,依据杂种小麦亲本农艺性状进行亲本优势型划分可以作为杂种小麦亲本选配的依据之一.在陕西关中地区以大粒×多穗型为杂种小麦强优势组合组配模式.     

籼稻根系活力与地上部分的关系

1998年早季在广州研究了不同籼稻类型根系活力与地上部分一些性状的关系,结果表明:（1）所有参试品种的根系活力在全生育期中均呈单峰曲线变化,最高值出现在幼穗第2次枝梗原基分化期。两系法杂交稻在生长前期根系活力增幅大,叶面积指数发展快。（2）根系活力在分蘖期与叶绿素含量呈显著正相关;在分蘖期和孕穗期与叶绿素a/b值呈显著负相关,并在幼穗第2次枝梗原基分化期与叶面积指数呈显著正相关,说明在水稻生长发育前期根系活力的强弱与地上部分叶、蘖的发展是相对应的。（3）根系活力与灌浆成熟后期的籽粒充实度达极显著正相关,根系活力强的品种,后期充实度高,相反则充实度低。     

栽培稻杂种不育性的遗传研究——Ⅲ.不同类型品种F_1花粉不育性的等位基因分化

以台中65等基因F_1不育系为遗传测验种,测定了栽培稻(O.sativa)45个品种在3个F_1不育基因座的基因型和等位基因的分化度。在S-E3基因座上,除Dular带有S_i/S_i基因型外,其余被测品种均带有S_i/S_i基因型。在S-E2和S-E5基因座上,籼型品种带有高频率的S_i基因,而粳型品种带有高频率的S_i基因。S_i和S_i均具有不同的分化度。籼型品种携带的S_i基因和粳型品种携带的S_i基因具有较高的分化度。中间型品种和广亲和品种的等位基因分化在S-E2基因座上与粳型品种相似,而在S-E5基因座上与籼型品种相似。此外,分析了各类型品种相互杂交F_1杂种在S-E2和S-E5基因座的杂合率、杂合度和杂合性。与籼/粳杂种相比,中间型品种(包括广亲和品种)与籼型和粳型品种杂交,F_1杂种均具有较低的平均杂合性,从而表现出较高的亲和性。因此,无论是杂种不育性还是杂种亲和性均由花粉不育基因控制。花粉不育基因也称为特异亲和基因。     

长穗偃麦草细胞质小麦核质杂种农艺性状的研究

长穗偃麦草细胞质小麦核质杂种与核共体进行了比较试验,结果证明：核质杂种株高降低５－８ｃｍ,抽穗期略有推迟,抗寒性有明显提高。其它农艺性状,如分蘖数,穗长,穗粒数,结实率等性状没有明显差异。但是在核质杂种中粒粒蛋白质含量增加了１１．７９％和２７．３３％,被分析的１７种氨基酸含量也是明显提高,提高幅度１２．３７－５３．０９％。     

不同类型水稻的组织培养和细胞悬浮培养

我们(1980)曾报道过晚粳稻台中育39和杂交水稻汕优6号幼穗、茎、叶鞘等外植体愈伤组织的诱导率、分化率及其试管苗得率的情况及其在温室、大田的性状表现(赵成章等1980),并指出水稻幼穗外植体具有很强的分化能力。因此,本实验以水稻的幼穗为材料,比较研究不同类型水稻品种幼     

Winter hardiness in trench celery

A total of 51 red and white commercial varieties of trench celery were grown and examined for winter hardiness at the National Vegetable Research Station. Although some plants of most varieties survived the winter, none showed a commercially useful degree of winter hardiness, in that none were marketable after moderate frost. The red varieties had a significantly better survival than the white varieties. In the first season, single plant selections were made from the varieties having both the highest percentage of winter survival and the best agronomic characters. Although some of the progenies derived from these selected plants by self-pollination showed a small increase in winter survival as compared with their parent varieties when both were grown in the second season, no plants of these progenies were sufficiently hardy to remain marketable after moderate frost. It was concluded that none of the varieties tested showed any promise as a source of winter hardiness to be used in a breeding programme, and that selection for one generation from within these varieties did not improve winter hardiness to a useful extent.     

香菇杂交子农艺性状与差异基因表达类型的相关性研究

以香菇(Lentinula edodes)4个菌株为亲本组成3个杂交组合,采用单孢菌株配对获得杂交子,观察锁状联合鉴别出真正的杂交子,测定杂交子及其亲本的农艺性状。在每个杂交组合中分别各选取3个杂交子,研究杂交子和亲本在子实体发育阶段差异基因表达情况。结果表明:杂交子共有4种基因表达类型:双亲沉默型(W1型),单亲沉默型(W2型),杂交子特异表达型(W3型),单亲表达型(W4型)。香菇杂交子农艺性状与基因差异表达类型的相关性分析表明:菌盖厚与双亲沉默型(W1型)呈极显著负相关,而菌柄长与单亲沉默型(W2型)呈显著负相关。     

Inheritance of frost resistance and winter hardiness in distant hybrids of wheat and amphiploids

The data on inheritance of frost resistance and winter hardiness of bread wheat lines obtained as a result of distant hybridization of wheat-rye and wheat-elymus amphiploids with durum and bread wheat were presented. It was shown that selection of the donors of valuable traits is sensible to make in later progenies of hybrids (F6-F7). So, it is possible to obtain the new initial breeding material for winter bread wheat selection with high frost tolerance, winter hardiness and early maturity. Hypotheses explaining the high frost resistance of hybrids are presented. The crosses of the octoploid amphiploids with durum wheat are more preferable for the alien traits introgression into wheat than the crosses with bread wheat.     

Genetic basis of photoperiodic control of summer and winter diapause in geographic ecotypes of the rice stem maggot, Chlorops oryzae

Chlorops oryzae Matsumura (Diptera: Chloropidae) is bivoltine in northern Japan but trivoltine in the southern part of the country. Larvae of the bivoltine strain (Akita, 39° N) develop without delay under L14:D10 but enter summer diapause in the mature larval stage under L15:D9. In contrast, larvae of the trivoltine strain (Aichi, 35° N) develop quickly under L15:D9 but enter summer diapause under L14:D10. The genetic basis of their different summer-diapause behavior was analyzed by reciprocal crossing between the two ecotypes and backcrossing to the hybrids. Although a polygenic system seems to be involved, there is a single gene on the X-chromosome exerting a major effect on summer diapause. The northern bivoltine ecotype has a longer critical photoperiod for the induction of winter diapause in the first larval stage and remains in diapause longer than the southern trivoltine ecotype. The differences in the critical photoperiod and the winter diapause duration between the two ecotypes seem to be controlled by a polygenic system but again a sex-linked or closely linked gene (or genes) plays a major role. The two geographic ecotypes differ significantly in summer- and winter-diapause traits, both of which are characterized by sex-linked inheritance. Despite this, no apparent sterility or inviability in hybrids between the ecotypes occurs.     

小麦的不同染色体组对G、S~v、D~2、M~u型细胞质“中国春”育性的影响

本文以Ｇ、Ｊｖ、Ｄ２、Ｍｕ型异细胞质“中国春”;小麦为母本与１１个不同染色体组类型小麦为父本进行杂交,观察当代的结实率,Ｆ１的育性与性状的变化、减数分裂行为,进一步探讨小麦的细胞质雄性不育与染色体组类型的关系。结果表明：当代结实率主要由父本染色体组类型决定,Ｆ１的育性表现十分复杂,同一父本与不同的异细胞质“中国春”杂交,有的表现可育,有的表现不育,细胞质有一定的影响。Ｆ１的性状,有的与细胞质类型有关,如熟期、雄蕊形态、生长期与抗病性等。选择适宜可获得有明显杂种优势的组合。有的细胞质类型可影响减数分裂行为使中期Ⅰ配对的染色体增加或减少,在四分期出现微核与异常四分孢子。     

Seasonal changes in glycerol content and cold hardiness in two ecotypes of the rice stem borer, Chilo suppressalis, exposed to the environment in the Shonai district, Japan

The rice stem borer, Chilo suppressalis, is divided into at least two ecotypes in Japan, the Shonai ecotype (SN) which is distributed in the northern part of Japan, and the Saigoku ecotype (SG) which is distributed in the southwestern region. Cold hardiness is positively correlated with the level of glycerol in both ecotypes. To investigate whether ecological distribution affects glycerol accumulation and cold hardiness development in these two ecotypes, overwintering larvae of the SN and SG ecotypes were concurrently exposed to the Shonai district. Obvious differences in the progress of glycerol accumulation and cold hardiness development in SN and SG larvae were found in early winter in the Shonai district. The levels of glycerol content and cold hardiness were low in October and high in January in both ecotypes, but those levels were different within this period (November and December) between ecotypes; the levels in SN larvae quickly reached their maximum, whereas, in SG larvae levels increased slowly. Under controlled conditions, the effect of the period of acclimation at 10 degrees C and subsequent low-temperature (5 degrees C) exposure on glycerol accumulation was investigated. These results indicated that glycerol accumulation in SN was stimulated by the progression of diapause termination, whereas a higher cumulative effect on glycerol production in SG was found when diapause was in a deep state.     

THE MAINTENANCE OF A CLINE IN THE MARINE SNAIL LITTORINA SAXATILIS: THE ROLE OF HOME SITE ADVANTAGE AND HYBRID FITNESS

Steep clinal transitions in one or several inherited characters between genetically distinct populations are usually referred to as hybrid zones. Essentially two different mechanisms may maintain steep genetic clines. Either selection acts against hybrids that are unfit over the entire zone due to their mixed genetic origin (endogenous selection), or hybrids and parental types attain different fitness values in different parts of the cline (exogenous selection). Survival rate estimates of hybrids and parental forms in different regions of the cline may be used to distinguish between these models to assess how the cline is maintained. We used reciprocal transplants to test the relative survival rates of two parental ecotypes and their hybrids over microscale hybrid zones in the direct-developing marine snail Littorina saxatilis (Olivi) on the rocky shores of Galicia, Spain. One of the parental forms occupies upper and the other lower shores, and the hybrids are found at various proportions (1–38%) along with both parental forms in a midshore zone a few meters wide. The survival rate over one month was 39-52% of the native ecotype on upper shores, but only 2-8% for the lower-shore ecotype. In contrast, only 4-8% of the upper-shore ecotype but 53% of large (> 6 mm) and 8% of small (3-6 mm) native lower-shore ecotype survived in the lower shores. In the midshores, both the two parental ecotypes and the hybrids survived about equally well. Thus there is a considerable advantage for the native ecotypes in the upper and lower shores, while in the hybrid zone none of the morphs, hybrids included, are favored. This indicates that the dimorphism of L. saxatilis is maintained by steep cross-shore selection gradients, thus supporting the selection-gradient model of hybrid zones. We performed field and laboratory experiments that suggest physical factors and predation as important selective agents. Earlier studies indicate assortative mating between the two ecotypes in the midshore. This is unexpected in a hybrid zone maintained by selection gradients, and it seems as if the reproductive barrier compresses the hybrid zone considerably.     

Successful crosses between Festuca arundinacea Schreb. and Dactylis glomerata L.

Summary Five F₁ plants have been obtained after extensive crossing between different ecotypes or varieties of Festuca arundinacea Schreb. and Dactylis glomerata L. The success did not appear to depend on specific treatments (spraying with -aminocaproic acid or gibberellic acid or pre-pollination with killed pollen from the seed parent), but the crossability is limited to exceptional plants.F₁ hybrids showed characteristics of both the parents. In four hybrids various developmental disturbances were observed (low viability, aneusomaty, absence of development of inflorescences). Only one hybrid consistently showed 2n=35 chromosomes, good viability and growth, however, it was sterile. After clonal propagation, attempts for polyploidization were started.     

Comparative analysis of photosynthetic characteristics and productivity in F2 hybrids of winter rye

Diversity of photosynthetic characteristics determined by plant genotypes provides the grounds for the increase in potential crop productivity by means of producing plant forms whose photosynthetic apparatus (PSA) has optimal size and functional efficiency. Parental forms of winter rye (Secale cereale L.) and their interline and intravarietal reciprocal F₂ hybrids were compared in terms of photosynthetic pigment (PSP) content, characteristics of chlorophyll a (Chl) fluorescence, some morphological traits, and grain productivity. At the booting and anthesis stages, significant divergence in chlorophyllous pigment content and Chl a fluorescence parameters was observed for winter rye inbred lines, rye varieties, and hybrids. The hybrids were revealed whose elevated grain productivity correlated with high PSP content and the highest photosystem II (PSII) activity. Analysis of correlations in reciprocal F₂ hybrids at booting and anthesis stages of rye development showed that accumulation of PSII is related to stem-forming capacity and to the flag leaf surface area. In reciprocal hybrids, the correlations between morphological traits, grain productivity, plastid pigments, and photochemical activity were subject to variations. The relationships between PSA parameters and grain productivity in winter rye F₂ hybrids varied depending on the developmental stage as well as on crossing combination; this relation was largely determined by the choice of pairs for hybridization, by direction of crosses, and by genetic features of parental forms.