水稻食味品质性状间相关性分析及其与叶片光合作用的关系

为明确优质稻米品质性状及其与叶片光合作用的关系,培育筛选优良食味水稻新品种,以河南省沿黄稻区8个优良食味水稻品种为试验材料,在大田栽培条件下,对稻米的直链淀粉含量、蛋白质含量、加工品质指标（糙米率、精米率和整精米率）和外观品质指标（垩白粒率和垩白度）等性状进行测定和分析,并对籽粒灌浆期水稻剑叶的光合速率进行检测。结果表明,8个供试优良水稻品种的糙米率、精米率和整精米率均较高,品种间的变异系数较低;稻米外观品质垩白粒率和垩白度在品种间差异较大,变异系数分别为39.73%和36.49%;影响稻米食味品质的直链淀粉、蛋白质含量和食味值在品种间变异系数相对较小,均低于5%。相关分析表明,蛋白质含量与食味值呈显著的开口向上的左偏抛物线关系（r=0.827*）,直链淀粉含量与食味值呈极显著的直线负相关关系（r=-0.905**）,糙米粒厚与食味值呈显著的开口向下的抛物线关系（r=0.747*）;外观品质指标、蛋白质含量和食味值与灌浆中后期的叶片光合速率均呈负相关关系,直链淀粉含量与之呈正相关关系。说明蛋白质和直链淀粉含量越低稻米的食味越好,在一定范围内,随着糙米粒厚的增加食味增加,而糙米粒厚大于2.1 mm,食味值反而下降;提高水稻灌浆中、后期叶片的光合速率,有利于改善稻米的外观和营养品质,而稻米直链淀粉含量增加,食味值下降。因此,水稻叶片的高光合效率在优质食味米选育方面存在一定的选择压力,合理调控水稻中后期叶片的光合速率对提高和改善稻米食味品质具有重要意义。     

华南优质杂交水稻品种选育与发展

本文针对华南广东、广西优质杂交稻育种的两个阶段进行了综述。第1个阶段为中等直链淀粉含量优质杂交稻发展阶段,育成了粒型较好、心腹白较少、透明度好的博A、秋A、美A、粤泰A、天丰A、五丰A、荣丰A和吉丰A等8个不育系,并利用其配组育成博优998、天优998、五优308等中等直链淀粉含量的优质杂交稻品种149个通过审定。此外,还利用两系不育系培矮64S配组育成培杂双七、培杂泰丰等9个中等直链淀粉含量的优质两系杂交稻品种通过审定。第2个阶段为低直链淀粉含量的优质杂交稻发展阶段,育成了粤丰A、泰丰A、野香A、广8A、丰田1A等15个优质不育系,并利用其配组育成泰丰优208、野香优莉丝、丰田优553等低直链淀粉含量优质杂交稻品种212个通过审定。同时,利用五山丝苗、粤农丝苗、五山油占等8个高产抗病兼用型优质常规稻作恢复系和优质恢复系华占与丙4114配组育成175个低直链淀粉含量优质杂交稻品种通过审定。从2015年开始,在每年的全国年推广面积前十大品种中,由华南直接育成或利用华南亲本合作育成的杂交稻品种占到一半以上,为我国优质籼稻产业发展发挥了巨大作用。最后还讨论了当前华南优质杂交稻存在问题和今后育种的发展方向。     

施氮量对津原E28产量和品质的影响

以津原E28为供试品种,研究不同氮肥施用量对该品种水稻产量和稻米品质的影响。结果表明:随着施氮量的增加,水稻产量增加,结实率降低,粒长、宽、厚降低,但当施氮量达到240 kg/hm2以后,各处理组差异不显著;随着施氮量的增加,稻米蛋白质含量显著增加,食味值下降,直链淀粉含量、碘蓝值和透过率变化各处理间差异不显著;对淀粉RVA图谱分析显示,随着施氮量的增加,最高粘度、热浆粘度、冷胶粘度均逐渐下降,且差异显著,崩解值和消减值也逐渐下降,但差异不显著。     

Physico-chemical Characteristics as Indicators of Starch Availability from Milled Rice

The hypothesis was tested that certain physico-chemical characteristics might be used as indicators of total starch availability and rate of starch availability of milled rice. Milled unparboiled (uPB) and parboiled (PB) rice samples (n=93) were characterized using standardized methods of physical tests and chemical analyses and anin vitromethod was used for measuring the rate of starch digestion on a subsample of rice (n=26). The rice varieties were dominated by medium long, bold rice grain with high amylose rice and intermediate gelatinization temperature (GT), but a wide range in all characteristics was measured. Small amounts of resistant starch (RS) were measured in the cooked rice, indicating virtually complete starch availability. The RS of PB rice (0·4 g/100 g rice as eaten) was significantly (P<0·004) higher than the RS of uPB rice (0·1 g/100 g) however. The rate of starch digestion was significantly affected by both variety and parboiling. The starch digestion index (SDI) values of the PB samples (mean value 73·7) were significantly (P<0·001) lower than those of the uPB samples (mean value 79·0). The apparent amylose content (AC) was the strongest determinant for SDI in both uPB and PB rice. The widths and shapes of the raw grains and the elongation after cooking were correlated significantly with SDI values for the uPB rice, while the relatively mild parboiling procedure followed in this study eliminated this correlation. The minimum cooking times were correlated significantly with the SDI values in the uPB samples.     

Characterization of waxy grain sorghum lines in relation to granule-bound starch synthase

The waxy phenotype, associated with endosperm containing little or no amylose, has been recognized in sorghum (Sorghum bicolor L. Moench) since 1933. Although variants of the waxy gene are well characterized in other cereals, the waxy trait has been assumed to be controlled by a single allele, wx, in sorghum. Recent improvements in technologies encourage re-examination of the waxy sorghums. The objectives of this research were therefore to identify and characterize sorghum lines with differing waxy alleles and to describe the actions of those alleles in crosses. Grain of eight waxy sorghum lines (BTxARG1, BTx630, Tx2907, B.9307, 94C274, 94C278, 94C289, 94C369), three wild-type checks (BWheatland, RTx430, BN122), and F₂ families from crosses among a subset of these lines were evaluated for presence or absence of granule-bound starch synthase (GBSS), the gene product of the wx locus, and wild-type vs. waxy endosperm. The F₂ segregation ratios were tested for fit to a 3:1 ratio using Chi-square analyses. Two distinctly different naturally occurring waxy alleles were identified: One with no GBSS (GBSS−), and one with apparently inactive GBSS present (GBSS+). We propose that the waxy allele with no GBSS be designated wx^a, and that waxy allele with apparently inactive GBSS present be designated wx^b. These two alleles are located in close proximity on the waxy locus. The wx^b allele is dominant to the wx^a allele in terms of GBSS production, and both are recessive to the wild-type Wx in terms of amylose content. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Genetical Studies on the Mode of Inheritance and Localization of the amo1 (High Amylose) Gene in Barley

In the high amylose starch mutant ‘Glacier AC38’, a single recessive gene designated amo1 is responsible for an amylose content of up to 45%. A rapid technique was established in order to evaluate the amylose/amylopectin ratio in half kernels. To localize this gene, crosses with multiple marker lines and trisormes were conducted. In addition, RFLP markers were used to determine their mapping distance to amo1. Two markers are located 2 cM and 7 cM, respectively, from amo1 on chromosome 5S (1HS). The relationship between the wx and amo1 genes was also examined and the role of the amo1 gene in starch synthesis is discussed.     

灵芝多糖提取与应用现状

阐述了灵芝多糖的理化性质、提取方法、影响提取率的因素及其应用效果。其提取方法主要有水提醇沉法和膜分离法。试验表明，灵芝多糖在抗肿瘤及免疫调节等方面具有显著的医药作用，并有广阔的应用前景。     

A Rapid Test Procedure for Estimating the Amylose Content of Pea Starch *)

Rapid estimation of the amylose content of pea starch is of particular importance in breeding for pea starches high in amylose. An amylose test for starch in fresh potato tubers was adapted for use with high-amylose pea flour. Wavelengths for photometric detection were slightly changed, and the iodine concentration could be reduced. Defatting of the flour was not necessary. Reproducibility of the analyses was good (s% <3; n = 95). Variability of amylose content was investigated for different potato, barley and pea varieties. An analysis of the F4-generation of a crossing experiment with peas underlined the specific suitability of this rapid test method for supporting breeders' activities.     

Developing gene-tagged molecular markers for functional analysis of starch-synthesizing genes in rice (Oryza sativa L.)

The granule-bound starch synthase(GBSS), starch branching enzymes 1 (SBE1)and 3 (SBE3) are major enzymes involved in starch biosynthesis in rice endosperm. Available sequences of Sbe1 and Sbe3 genes encoding corresponding SBE1 and SBE3 have been used to identify homologous regions from genome databases of both the indica rice 93-11 and the japonica rice Nipponbare. Sequence diversities were exploited to develop gene-tagged markers to distinguish an indica allele from a japonica allele for both Sbe1 and Sbe3 loci. With these newly developed gene-tagged markers and available Wx gene markers, the roles of these starch-synthesizing genes (Sbe1, Sbe3, and Wx) in determining amylose content (AC) in the rice endosperm were evaluated using a double-haploid (DH)population derived from a cross between the indica rice cv. Nanjing11 and the japonica rice cv. Balilla. Only the Wx and Sbe3 loci had significant effects on the AC variation. On average, indica Wx ^a genotypes showed ∼9.1% higher AC than japonica Wx ^b genotypes, while indica Sbe3 ^a genotypes showed ∼1.0% lower AC than japonica Sbe3 ^b genotypes. A significant interaction was also observed between Wx and Sbe3 loci whereby the amylose content was 0.3% higher in Sbe3 ^a than Sbe3 ^b genotypes in the presence of the Wx ^a allele, but it was lower by 2.3% in the presence of the Wx ^b allele. Overall, polymorphisms at the Wx and Sbe3 loci together could account for 79.1% of the observed AC variation in the DH population. The use of gene-tagged markers in marker-assisted selection and gene functional analysis was also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.