Comparison of Grain Quality Characteristics Between F1 Hybrids and Their Parents in Indica Hybrid Rice

Sixteen widespread elite indica parents including seven CMS lines and nine restorer lines, and their 63 F1 hybrids were chosen to compare the eleven traits of grain quality. Overall results showed that the frequency of negative over dominance, dominance and partial dominance was much higher than that of positive ones and heterosis, indicating that the values of F1 hybrids were generally lower than the means of their parents in quality characteristics. There existed apparent disparity in grain quality performance among F1 hybrids varied with the traits. The characteristics of chalky area percentage, chalky grain percentage, gel consistency and head rice recovery had a great variation in all kinds of tested heterosis indices including the mid parent heterosis index, over high value parent heterosis index and over low value parent heterosis index, which suggested that special attention should be paid to the selection of F1 hybrids in these traits in breeding. The mean values of F1 hybrids were significantly lower than those of their higher parents in all the traits but close to or significantly lower than those of their mid parent values except for kernel length and amylose content; and significantly higher than those of their lower parents except for brown rice recovery, milled rice recovery and gel consistency.     

Comparison of Grain Quality Characteristics Between F1 Hybrids and Their Parents in Indica Hybrid Rice

Sixteen widespread elite indica parents including seven CMS lines and nine restorer lines, and their 63 F1 hybrids were chosen to compare the eleven traits of grain quality. Overall results showed that the frequency of negative over-dominance, dominance and partial dominance was much higher than that of positive ones and heterosis, indicating that the values of F1 hybrids were generally lower than the means of their parents in quality characteristics. There existed apparent disparity in grain quality performance among F1 hybrids varied with the traits. The characteristics of chalky area percentage, chalky grain percentage, gel consistency and head rice recovery had a great variation in all kinds of tested heterosis indices including the mid-parent heterosis index, over high-value parent heterosis index and over low-value parent heterosis index, which suggested that special attention should be paid to the selection of F1 hybrids in these traits in breeding. The mean values of F1 hybrids were significantly lower than those of their higher parents in all the traits but close to or significantly lower than those of their mid-parent values except for kernel length and amylose content; and significantly higher than those of their lower parents except for brown rice recovery, milled rice recovery and gel consistency.     

Selection of Suitable Parents in the Development of Potato Hybrids in Bangladesh

Potatoes(Solanum tuberosum L)are the thirdlargest food crop in Bangladesh following rice andwheat and make a major contribution to the total foodsupply of the country.Although in many westerncountries potato is the number one staple food,it is al-most entirely used as a vegetable in Bangladesh.Thepotato is a short duration crop that produces a largeamount of calories in a short period of time[1].Thepotato produces more protein and calories per unitarea per unit time than any other major food…     

Synergistic and antagonistic interactions between potassium and magnesium in higher plants

Magnesium(Mg)affects various critical physiological and biochemical processes in higher plants,and its deficiency impedes plant growth and development.Although potassium(K)-induced Mg deficiency in agricultural production is widespread,the specific relationship of K with Mg and especially its competitive nature is poorly understood.This review summarizes current knowledge on the interactions between K and Mg with respect to their root uptake,root-to-shoot translocation and distribution in plants.Their synergistic effects on certain physiological functions are also described.The antagonistic effect of K on Mg is stronger than that of Mg on K in root absorption and transport within plants,indicating that the balanced use of K and Mg fertilizers is necessary for sustaining high plant-available Mg and alleviating K-induced Mg deficiency,especially in plant species with high K demand or in highavailable-K soil.The relationship between Mg and K in plant tissues may be antagonistic or synergistic depending on plant species,cell type,leaf age,source-and sink organs.There are synergistic effects of K and Mg on photosynthesis,carbohydrate transport and allocation,nitrogen metabolism,and turgor regulation.Definition of optimal K/Mg ratios for soils and plant tissues is desirable for maintaining proper nutritional status in plants,leading to a physiological state supporting crop production.Future research should concentrate on identifying the physiological and molecular mechanisms underlying the interactions between K and Mg in a given physiological function.     

α and β-galactosidase activities and oligosaccharide content in peanuts

Thirty-three peanut cultivars were examined for their alpha-1,6 and beta-1,4 galactosidase activities and oligosaccharide contents along with proximate compositions. The average moisture, protein, fat, ash, and carbohydrate contents were: 4.9%, 26.6%, 43.1%, 2.3% and 23.1%, respectively. The corresponding coefficients of variation were: 5.2%, 10.1%, 7.2%, 7.8% and 15.7%, respectively. Raffinose and stachyose contents (%) ranged from 0.05 to 0.12 and 0.31 to 0.61, respectively. The specific activity (micromol product/min/mg protein) of crude preparation of alpha-galactosidase for the 33 cultivars ranged from 1.096 to 2.784 for the non-germinated seeds and from not being detected in some samples up to 2.432 for the germinated seeds; the mean values for non-germinated and germinated seeds were: 1.781 and 1.410, respectively. The specific activity of beta-galactosidase ranged from 0.101 to 1.727 in the non-germinated seeds and from not being detected in some samples up to 0.898 in the germinated seeds. Germination decreased the activity of both galactosidases significantly (p < or = 0.05).     

Awards and training course

Prof YUAN Longping, Director of Hunan Hybrid Rice Research Center (HHRRC). won the Alan Shawn Feinstein World Hunger Awards for his research and education in Brown University of America Apr 14, 1993.     

Correlations between ultrastructure and photosynthesis in leaves of rice and barnyard-grass

The ultrastructure of the leaves of rice(Oryza sativa)and barnyardgrass(Echinochloa crus-galli)in their milking stage were studied withelectron microscopy.The content of chloro-     

Fertilizer rate and β-galactosidase and peroxidase activity in pepper fruit at different stages and years of harvest

Beta-galactosidase and peroxidase are enzymes reported to have roles in pepper maturation. Fertilizer rate may affect activity of these enzymes in fruit maturing on the plant. Nine pepper cultivars, five non-pungent and four pungent, were fertilized at two rates in field plots in 1997 and 1998 at Lane, OK, USA. Fruit were harvested at mature green, turning, and red color developmental stages, and assayed for beta-galactosidase and peroxidase activity. Overall fruit beta-galactosidase activity increased as fertilizer rate increased, and was highest in red fruit. Fertilizer rate and fruit developmental stage did not affect peroxidase activity in 1997, but peroxidase activity was highest in red fruit in 1998. Enzyme activity appeared to be cultivar dependent, and patterns differed in both years. Activities of both enzymes were higher at the red stage in many of the non-pungent peppers than in pungent peppers. These data suggest that increased fertilizer affects the activity of at least one enzyme in fruit maturing on the plant. Cultural practices affecting enzyme activity may be used to modify concentrations of components in plants that are important for human consumption.     

Relationships between zeatin and zeatin riboside contents and grain filling of rice

Zeatin(Z)and zeatin riboside(ZR)are natu-rally-occurring and predominant transportablecytokinins in some higher plants.In thisstudy,the total contents of Z and ZR weremeasured in grains and roots,respectively,and their relationship with grain filling wereanalyzed.The grain filling percentage(GFP)and fertilized-grain filling percentage(FGFP)of rice cultivars IR72,IR 65600-42-5-2,IR65600-127-2-3,and IR 65598-112-2 grown infield and cultivars IR72,IR57298-174-1-1R,     

杂交籼稻亲本种子休眠性与F1的相关及配合力研究

 利用19个核质互作型不育系和9个恢复系,配制了109个杂交组合。花后35 d收获种子,分别检测每个杂交组合F1及其亲本种子在不剥壳和剥壳情况下的休眠指数。采用5×5 NCⅡ遗传设计配制了25个组合,利用其种子的休眠指数分析了配合力。结果表明,在不剥壳情况下,F1种子的休眠指数与双亲种子的休眠指数以及中亲值呈极显著正相关。109个组合中,82个组合超过中亲值,43个组合超过高亲值,具有明显的中亲优势。去除稃壳的双亲及F1种子的休眠指数均大幅度下降,表明稃壳对种子休眠性具有重要作用,但剥壳后双亲种子和F1种子休眠性之间的关系,仍然存在与不剥壳时相似的趋势。稃壳对种子休眠性的影响主要取决于F1的基因型,而不受控于母体稃壳本身。不育系、恢复系休眠性的一般配合力方差和组合的特殊配合力方差占总遗传方差的比例分别为59.2%、31.1%和9.7%,三者均达到极显著水平,说明基因的加性作用占主导地位。不育系Ⅱ112A 种子休眠性的一般配合力最高,D62A次之;恢复系以IR112一般配合力最高,2786次之。它们是选配强休眠杂交组合的优良亲本材料。     

杂交大豆配合力及杂种优势分析

为了提高杂交大豆育种效率,进一步提高杂交大豆产量。本研究以5份大豆细胞质雄性不育系为母本,12份恢复系为父本,采用NCⅡ设计方法组配60个杂交组合,对产量、单株荚数、单株粒数和每荚粒数分别进行杂种优势、配合力效应、及其与F1性状的相关性分析。结果表明,F1产量性状中亲优势组合占全部组合的55%,超高亲优势组合占30%,中亲和超高亲优势均?20%的占15%。单株荚数、单株粒数、每荚粒数等产量相关性状的中亲优势组合分别占55%、56.67%和23.33%,超高亲优势率均为负值。17份亲本材料的一般配合力（general combining ability,GCA）变化范围为-27.94%～56.62%,其中6份材料表现为正效应;30个杂交组合的特殊配合力（special combining ability,SCA）为正值,占总体的50%。此外,SCA与F1籽粒产量和单株荚数的杂种优势及其性状值均相关;GCA与产量性状值和单株粒数的中亲优势呈极显著相关,与单株荚数的中亲优势、单株粒数、每荚粒数的超高亲优势及性状值呈显著相关;各性状SCA与GCA之间不相关。单株荚数和单株粒数对产量的贡献较大。产量杂种优势强的组合双亲除具有高的一般配合力,而且兼具有较高的特殊配合力。     

杂交稻淀粉RVA谱特征值的配合力及杂种优势研究

以6个籼型三系杂交稻不育系和5个恢复系按不完全双列杂交配制的30个杂交稻组合及其亲本为材料,对其淀粉RVA谱特征值进行了测定和分析。结果表明:淀粉RVA谱特征值在各组合间均存在极显著遗传差异,其加性效应和非加性效应对杂交稻淀粉RVA谱特征值均存在极显著的影响,并以加性效应为主;杂交稻亲本RVA谱特征值一般配合力(GCA)效应高的,其后代特殊配合力(SCA)效应不一定高;杂交稻母本RVA谱特征值GCA方差在总的基因型方差中所占比重远远大于父本和组合SCA方差,表明杂交稻淀粉RVA谱特征值主要受不育系的影响;杂交稻淀粉RVA谱特征值的竞争优势与母本的GCA极显著正相关,且决定系数较高,表明杂交稻母本的一般配合力高,其所配杂交稻组合的竞争优势也强;杂交稻淀粉RVA谱特征值的峰值黏度存在明显的超高亲优势;糊化开始温度存在超低亲优势;其他性状存在中亲优势。     

12个粳稻新不育系的配合力及利用价值评价

以12个新育成的BT型粳稻不育系和8个恢复系为亲本,采用p×q不完全双列杂交(NCⅡ)设计,对其F1代13个农艺性状的配合力进行了分析。除单株穗数的特殊配合力方差不显著外,所有性状的一般配合力方差和特殊配合力方差均达到极显著水平。所测性状主要受亲本一般配合力的影响,主穗实粒数、结实率、单株产量和收获指数受组合特殊配合力的作用较突出。穗长、穗颈长、结实率和收获指数受不育系的影响较大,其余性状均受恢复系的影响较大。亲本一般配合力和组合特殊配合力是相互独立的。一般配合力和特殊配合力与杂种优势呈极显著正相关。不育系以六盐A、丹阳941A、98G26A、99 9A、香粳8016A和95122A较好,有较大的应用潜力;恢复系以C418、J16、晚161和C76较好。     

两系杂交籼稻配合力分析

以5个新育成的籼型水稻光温敏核不育系和生产上广泛应用的不育系培矮64S为母本,6个新育成的恢复系为父本,采用NCⅡ设计配制36个组合,分别在海南和湖北进行试验(完全随机区组设计,3次重复）,考查单株产量等10个主要农艺性状,分析配合力。大多数性状的一般配合力和特殊配合力方差达到显著或极显著水平,各性状的一般配合力方差均大于特殊配合力方差,表明基因的加性作用大于非加性作用。5个新育成的不育系产量的一般配合力效应没有显著差异,但都显著高于对照不育系培矮64S;华885S的产量一般配合力效应最高,特殊配合力方差较大,是参试不育系中产量配合力最好的亲本;华893S的每穗总粒数和每穗实粒数的一般配合力效应最高,特殊配合力方差最大,是提高每穗粒数的优良亲本;播始历期以华328S表现最好,以华328S作母本可以选育到生育期变化较大的组合,既可以培育中籼型组合,也可以培育晚籼型组合;株高一般配合力以华884S的负效应最高,特殊配合力方差显著大于组合平均值,表明用华884S作母本,容易选育出植株较矮、抗倒性较强的组合。恢复系中,华恢2185的产量一般配合力效应表现最高,特殊配合力方差最大,千粒重、穗长、结实率和播始历期的一般配合力效应均排在参试恢复系首位,是一个理想的亲本;株高、每穗总粒数和着粒密度的配合力,以华1108表现最好。特殊配合力效应最大的前10个组合和单株产量最高的前10个组合顺序完全对应,表明在水稻杂种优势利用中,亲本之一有良好的一般配合力效应,另一个亲本或双方都具有良好的特殊配合力,就有可能育成强优势组合。     

杂交水稻苗期耐淹涝特性及其与亲本的关系

经对生产上主栽的野败型三系杂交组合及其亲本苗期耐淹涝能力的比较研究，杂交稻的耐淹涝能力的平均优势明显，且以显性效应为主。恢复系效应大于不育系；杂交稻淹涝后生存率与恢复系呈极显著正相关，与不育系呈显著正相关。杂交稻的耐淹涝表现以偏父型和中间型为主（80％以上），偏母型比例低。恢复系、不育系耐淹涝能力强的，配出的杂交稻耐淹涝能力更强。     

基于3个甘蓝型春油菜Pol CMS的优良恢复系选育

为选育出优良的恢复系父本,能够与春油菜区优良的春性甘蓝型油菜波里马细胞质雄性不育系（Pol CMS）配制出强优势杂交组合,先利用简化基因组测序技术（SLAF-seq）开发3个不育系和118个恢复系的SNP标记,对材料进行聚类分析,根据父母本花期相遇原则,从每一类选取数量不等的恢复系,共40个恢复系,分别与3个不育系采用NCⅡ设计配制120个杂交组合,分别进行配合力效应、杂种优势及双亲遗传距离与杂种表现的相关性分析。结果表明：遗传聚类将121份甘蓝型油菜资源分为5大类,大多数相同类型的品系被聚在了同一类,3份不育系均被聚在了第Ⅴ类;43份亲本的一般配合力（general combining ability,GCA）的变化范围为-20.78～30.42,恢复系R83、R107和R13的GCA较大,不育系GCA较大的为S3（105A）,特殊配合力较大的组合有S3×R13、S1×R48、S3×R11、S2×R89;组合S3×R13的产量超标优势和超亲优势最大,分别为37.12%和42.52%。遗传距离与单株产量呈极显著正相关,相关系数为0.390。与3个不育系组配的杂交组合中,产量排名前20位的亲本恢复系大部分来自和不育系遗传距离较大的Ⅰ类,并且在春油菜区大面积推广的品种,如青杂2号、青杂7号、青杂9号、青杂12号,均为被聚在Ⅰ类的恢复系与不育系S3（105A）组配的杂交种。因此认为,（S×Ⅰ类恢复系）组配模式可以获得强优势甘蓝型春油菜杂交组合。该研究不仅为后续甘蓝型油菜杂交种选育提供了亲本选择的分子依据,也将促进春油菜区的杂交育种进程。     

黑龙江杂交粳稻产量相关性状配合力及遗传参数分析

按照不完全双列杂交(NCII)设计,以6个恢复系为父本、3个不育系为母本共配制18个杂交粳稻组合,分析了产量相关性状的配合力及遗传参数.结果 表明,杂交组合的产量和结实率受母本的影响大于父本,每穗实粒数更多地依赖恢复系,穴穗数和千粒重则受双亲的共同影响.遗传分析表明,主要受基因加性效应影响的性状为穗实粒数,主要受非加性...     

杂交粳稻主要农艺性状配合力的研究(英文)

 选用7个具有不同细胞质的粳稻雄性不育系与5个恢复系配组,测定了35个不完全双列杂交组合12个性状的配合力。结果表明,杂交粳稻F_1性状的形成,除了穗数主要受不育系一般配合力的作用以及单株产量和生物产量未发现恢复系一般配合力的作用以外,其余性状均同时受不育系,恢复系一般配合力和组合特珠配合力的作用。不育系和恢复系的一般配合力比组合特殊配合力起着更为重要的作用,而在一般配合力中,不育系的作用更大。据此认为,杂交粳稻强优势组合的选配,应特别重视不育系的选育;而在恢复系的选育方面,应注意类型上的多样化。文中根据主要经济性状配合力效应的综合表现对参试亲本的优劣作了评价,推荐BT型六干辛A、D型南粳34A和宁恢3-2、77302-1为优良的三系亲本:并参考组合的实际表现,鉴定出六千辛A/77302-1、六千辛A/宁恢3-2、南粳34A/77302-1和南粳34A/宁恢3-2等优良组合。这些结果与育种实践相符,表明配合力研究对杂交优势育种有指导意义。