Why are There Indica Type and Japonica Type in Rice?——History of the Studies and a View for Origin of Two Types

On the bases of archaeological discoveries, the earliest domestication of rice has been confirmed in the middle and lower Changjiang River basin, while in the region wild rice populations are found in shallow swamps under a climate with freezing winter cold. These findings lead us to-examine the past ideas about domestication and differentiation of rice. Historically, in 1930s two sub-species, indica and japonica, were proposed on the basis of sterility in F1 hybrids between them. Soon after that, the two types were classified by the associations of a number of genetically independent traits. The characteristic associations of traits have been explained by the hybrid sterility or reproductive barriers which were assumed to comprise a set of duplicate recessive lethal genes and to be an inner genetic mechanism to lead to the varietal differentiations In 1980s, the hybrid sterility between Indica and Japonica types was analyzed, and Indica, Japonica, and wide-compatibility type which gives fertile hybrids when cross to Indica and Japonica types, are proved to contain an allele, S5＇, S5＇ and S5^n, respectively at a locus on chromosome 6. And those gametes having Sj allele are found to be partially aborted in the hybrid genotypes of S5＇/S5＇ while no gamete abortion occurs in S5＇/S5^n and S5＇/S5^n genotypes. Since then, the gene S5^n has been used in hybrid rice breeding to obtain fertile and vigorous hybrids between subspecies, and the long-disputed problem of hybrid sterility has been solved. Also in such studies the characteristic association of traits found in each of vadetal groups is better explained by founder effects. On the other hand, a large number of native cultivars of rice were surveyed with enzyme polymorphism in 1980s and later with molecular markers. As a result, profound genetic diversity is found in cultivated rice as well as in wild rice. These findings seem to lead us to the idea of multiple independent domestications of rice. However, before reaching such a conclusion, at least two factors, i.e., long-distance-dissemination of some genotypes and the possibilities of introgression by local wild rice to primitive cultivars need to be examined. Taking the two factors as well as the historical events into consideration, it is considered here that the perennial japonica cultivars which are close to wild rice in the Changjiang River basin were disseminated to East India through Assam or along the Bengal Bay, where they were transformed under the introgressions of local wild rice and formed a secondary center, from which some genotypes seem to be disseminated to colonies in Southeast Asia under the influence of Hinduism. Later some of the genotypes were introduced into China and constituted so called Indica type. This may be a reasonable picture for the varietal differentiation.

Relationship Between Plant Type and Grain Quality of Japonica Hybrid Rice in Northern China

Plant type and grain quality are two major aspects in rice breeding. Using canonical correlation analysis and canonical redundancy analysis, the relationship between plant type traits and rice grain quality traits was studied with 100 crosses derived from 10 sterile lines × 10 restorer lines. There was a complex relationship between parts of the traits of the two aspects. The angle of the 2nd leaf from the top and single panicle weight played important roles in plant type system and amylose content and grain length in grain quality system. The angle of the 2nd leaf from the top, plant height and single panicle weight had a great effect on grain quality traits, and amylose content, brown rice rate and translucency were easily influenced by plant type traits. Selection index model indicated that japonica hybrid rice in Northern China with good quality was characterized by broad flag leaf and 2nd leaf from the top, narrow and short 3rd leaf from the top, low plant height, short culm, long and more panicles and low single panicle weight.

A Preliminary Study on the Relationship Between the Indica-Japonica RAPD Differentiation of Parents and Heterosisin Dian Type Hybrid Rice

The relationship between the indica-japonica differentiation of parents and heterosis of hybrid in rice was studied with 10 sterile lines, 10 maintainer lines of the sterile lines, 38 restorer lines of Dian type hybrid rice and 40 hybrids derived from the sterile lines and restorer lines. The results indicated that there was a parabolic correlation between the indica-japonica differentiation of parents detected by RAPD markers and heterosis of hybrid rice. When certain indica-japonica differentiation of parents exists, the percentage of combinations with positve heterosis and the mean heterosis of hybrids were high. But that didn't mean too much difference of parents could lead to stronger hetesosis, that meant overdiffernt parents seldom bring positve het-erotic hybrids. Suitable difference of percent of indica alleles of parents of stronger heterotic hybrid was 12 -16%.

Genetic Analysis on Plant Type of Northern Japonica Hybrid Rice

This study was designed to analyze the genetic relationship of the morphological traits of the northern japonica hybrid rice. The genetic relationship of the morphological traits of the 100 cultivars combined by the 10 sterile lines and the 10 restore lines was studied by using the principle component analysis and the SAS and QGA. The results showed that compared with the female parent, most of the morphological traits related closely to their father. The additive genetic effect and the dominant genetic effect appeared significantly, and the former was more significant than the latter. Genetic correlation analysis indicated that high plants or high plants with more leaves were in favor of improving the number and the weight of the spike and producing the hybrid vigor. The important factors influencing the plant type of the northern japonica hybrid rice were the plant height （PH）, the angle of the flag leaf （FLA）, flag leaf length （FLL）, and the weight of the shoots and leaves （SLW）, respectively. The morphological traits system of the northern japonica hybrid rice was very complex, and the restore line should be given more importance compared with the sterile line, and PH, FLA, FLL, and SLW should be considered first in the plant type breeding.

Comparisons of Protein Composition of Grains at Different Positions in Panicles between Erect and Curved Panicle Type Japonica Rice

Under field conditions, three erect panicle type japonica dee cultivars and three curved panicle type japonica rice cultivars were applied as experimental materials to investigate the differences of protein composition of grains at different positions in panicles between two different panicle types of japonica rice. Accord- ing to the results, the panicle type of japonica rice had no direct correlation with albumin content, globulin content, prolamin content and glutelin content in rice, variations of protein composition of grains at different positions in panicles. There were certain correlations between soluble protein contents at different grain posi- tions in the same panicle and the flowering order of glumous flowers in the panicle. Albumin content, prolamin content and glutelin content in grains on secondary rachis branches of two panicle types （erect and curved） of japonica rice cuhivars were higher than that on primary rachis branches, while globulin content exhibited an opposite trend. Globulin content, prolamin content and glutelin content in grains at different positions demonstrated a descending order of bottom 〉 middle 〉 top, while albumin content exhibited an opposite trend. The interactions between primary and secondary rachis branches and among top, middle and bottom rachis branches significantly affected soluble protein contents.

Relationships of Panicle Type Index with Subspecies Characteristics and Yield Traits in Filial Generation of Crosses between Indica and Japonica Rice

Two recombinant inbred line （RIL） populations, one derived from a cross between Zhongyouzao 8 （indica） and Toyonishiki （japonica） and the other from a cross between Qishanzhan （indica） and Akihikari （japonica）, were grown in Liaoning and Sichuan Provinces, China, to study the panicle type index （PTI, the ratio of a number of node position on panicle axis where the secondary branch with the most numerous secondary branch grains is located to the number of primary branches） and its relationships with subspecies characteristics and yield traits. With continuous distribution of PTI and numerous of lines with different PTIs in the progenies, indica-japonica hybridization could be a method for breeding cultivars with ideal panicle type. PTI was significantly influenced by environments, with a significant decrease from Liaoning to Sichuan A significantly negative correlation was found between PTI and most of subspecies characteristics. PTI varied remarkably with different subspecies types. As a whole, it showed a trend of indica （H）〉indicalinous （H＇）〉japonicalinous （K＇）〉japonica （K） However, it is not appropriate to regard PTI as a parameter for subspecies classification in rice because it was recombined in the filial generations of cross between indica and japonica rice. The negative correlations were found between PTI and most of panicle characteristics, as well as yield-related traits. Based on PTI, most of lines from the two populations were middle dominant panicle type （the number of grains on the secondary branch is numerous in middle position of the panicle） and lower dominant panicle type （the number of grains on the secondary branch is numerous in lower position of the panicle and becomes less towards the top of panicle） with significant yield advantages.

Suitable growing zone and yield potential for late-maturity type of Yongyou japonica/indica hybrid rice in the lower reaches of Yangtze River, China

Late-maturity type of Yongyou japonica/indica hybrids series （LMYS） have shown great yield potential, and are being widely planted in the lower reaches of Yangtze River, China. Knowledge about suitable growing zone and evaluation of yield advantage is of practicall importance for LMYS in this region. Fifteen LMYS, two high-yielding inbred japonica check varieties （CK-J） and two high-yielding hybrid indica check varieties （CK-I） were grown at Xinghua （119.57°E, 33.05°N） of Lixiahe region, Yangzhou （119.25°E, 32.30°N）of Yanjiang region, Changshu （120.46°E, 31.41°N）of Taihu Lake region, and Ningbo （121.31°E, 29.45°N） of Ningshao Plain in 2013 and 2014. The results showed that maturity dates of the 15 were later than the secure maturity date at Xinghua and 6, 14 and 15 LMYS were mature before the secure maturity date at Yangzhou, Changshu and Ningbo, respectively. One variety was identified as high-yielding variety among LMYS （HYYS） at Yangzhou, 8 HYYS in 201：3 and 9 HYYS in 2014 at Changshu, 9 HYYS at Ningbo. HYYS here referred to the variety among LMYS that was mature before the secure maturity date and had at least 8% higher grain yield than both CK-J and CK-I at each experimental site. Grain yield of HYYS at each experimental site was about 12.0 t ha-1 or higher, and was significantly higher than CK varieties. High yield of HYYS was mainly attributed to larger sink size due to more spikelets per panicle. Plant height of HYYS was about 140 cm, and was significantly higher than check varieties. Significant positive correlations were recorded between duration from heading to maturity stage and grain yield, and also between whole growth periods and grain yield. HYYS had obvious advantage over check varieties in biomass accumulation and leaf area duration from heading to maturity stage. Comprehensive consideration about safe matudty and yield performance of LMYS at each experimental site, Taihu Lake region （representative site Changshu） and Ningshao Plain （representative site Ningbo） were thought suitable growing zones for LMYS in the lower reaches of Yangtze River. The main factors underlying high yield ofHYYS were larger sink size, higher plant height, longer duration from heading to maturity stage and whole growth periods, and higher biomass accumulation and leaf area duration during grain filling stage.

Lonicera japonica-induced inhibition of interleukin-1 beta thermogenesis and E-type prostaglandin receptor-3 expression in the preoptic area of rabbits

BACKGROUND： It has been shown that interleukin-1β（IL-1β） can induce fever by activating vascular endothelial cells and macrophages of the supraoptic crest to generate prostaglandin E2, which binds with receptors of the thermo-sensitive hypothalamic neurons. Lonicera japonica is one of the medicinal plants used widely in Asia for its antipyretic properties. However, these mechanisms have not yet been intensively studied. OBJECTIVE： To investigate the antipyretic effect and mechanisms of Lonicera japonica on IL-1β- induced febrile New Zealand rabbits by observing expression changes of E-type prostaglandin receptor-3 （EP3） mRNA in the preoptic anterior hypothalamus （POAH）. DESIGN： A randomized controlled study. SETTING： Electrophysiological Laboratory at the Department of Pathophysiology, Medical College of Jinan University; Department of Orthopaedics, First Hospital Affiliated to Medical College of Jinan University. MATERIALS： The experiment was performed from April to December 2005, using a total of 32 New Zealand white rabbits of both sexes, weighing 1.5 2.0 kg. All the animal experiments were performed according to the internationally accepted ethical guidelines. Lonicera japonica injection was purchased from Huanghe pharmaceutical factory of Xi＇an, China. IL-1βwas purchased from Sigma, USA. METHODS： A total of 32 rabbits were divided randomly into four groups： ① Normal saline （NS） control group;② Lonicerajaponica treatment group; ③ IL-1βtreatment group; and ④Lonicerajaponica plus IL-1βtreatment group. In the first 3 groups, the rabbits were given separate intravenous （i.v.） injections of l mL NS, l mL Lonicera japonica, and 100 ng IL-l β （dissolved in 0.9% NS without pyrogen）. In the Lonicerajaponica plus IL-1βgroup each rabbit was given i.v. injections of l mL NS and, 30 minutes later, 100 ng IL-1 β. MAIN OUTCOME MEASURES： Colonic temperature of each rabbit was measured at 0, 10, 20, 30, 40, 50, 60, and 70 minutes after injection and the maximum temperature rise （ A T） and the temperature response index after l hour （TRII） was calculated. Subsequently, in situ hybridization （ISH） was done with an ISH kit, EP3 mRNA expression in the POAH of all groups was measured （number of positive cells and average gray scale value）. RESULTS： A total of 32 rabbits were included in the result analysis, without any loss, （i） A T and TRII： there was no significant difference between the Lonicera japonica group and NS group （P 〉 0.05）. The IL-1β group was significantly greater compared to NS group （P 〈 0.01）. The Lonicera japonica plus IL-1β group was significantly less than the IL-1β group （P 〈 0.05）. ② In the NS and Lonicera japonica groups, the EP3 mRNA expression was negative （no coloration） or only weakly positive （only a few brown yellow particles in the cytoplasm cells could not be identified）. The number of positive cells and the average gray scale value were not significantly different between the two groups （P 〉 0.05）. In the IL-1β group, the number of positive cells was remarkably higher and the average gray scale value was lower than the NS group （P 〈 0.0 l）. In the Lonicera japonica plus IL-1β group, the number of positive cells was significantly less than the IL-1β group （P 〈 0.05）. However, the average gray scale value was greater than the IL-1β group （P 〈 0.05）. CONCLUSION： Lonicera japonica has obvious antipyretic effects on IL-1β-induced febrile rabbits and acts by inhibiting expression of EP3 mRNA in the POAH.

粳稻穗型性状与谷粒性状的相关性研究

以247份粳稻品种为试材,分析了穗型性状与谷粒性状间的相关性。结果表明,8个性状变异系数在4.8%~31.2%,穗型性状、谷粒性状中各性状平均变异系数分别为22.2%、7.8%。粒型因子、粒重因子、粒数因子、结实因子、穗长因子是影响粳稻品种穗型性状和谷粒性状综合表现的主要因子。穗型性状、谷粒性状间存在复杂相关性。同时,粳稻直立穗型、半直立穗型、弯曲穗型品种具有不同的穗型性状和谷粒性状。

仿刺参过氧化氢酶的理化性质

利用重组工程菌BL21(DE3)/pET-28c-Aj-CAT外源表达了具有抗氧化活性的重组仿刺参过氧化氢酶(rAj-CAT)。重组rAj-CAT在405 nm处具有一个特征峰谱,且该峰谱不受Na_(2)S_(2)O_(4)的影响。典型的过氧化氢酶抑制剂如3-氨基-1,2,4-三唑、盐酸羟胺和叠氮化钠对rAj-CAT具有显著抑制作用。结果表明,此海参种属的过氧化氢酶属于典型的单功能过氧化氢酶。对重组rAj-CAT蛋白的最适酶活条件进行检测,确定rAj-CAT在较低温度范围(4~30℃)都具有降解H_(2)O_(2)的作用,最适酶活温度为10℃;rAj-CAT具有较宽的pH耐受范围,在pH 4.0~11.0都具有催化活性;rAj-CAT也能耐受多种金属离子和化学物质,包括Triton X-100、吐温20和EDTA;但DTT、β-ME、SDS、胰凝乳蛋白酶和胰蛋白酶对rAj-CAT水解H_(2)O_(2)的活性具有较强的破坏作用。结果表明,海参种属的Aj-CAT是一种能够在较低温度时具有较高活性的过氧化氢酶,并且酶学性质稳定。

金银花胡萝卜微管蚜发生规律及防治适期研究

目的:明确金银花胡萝卜微管蚜越冬卵和春季发生蚜型的形态特征和发生规律。方法:2022年2月,在田间观察胡萝卜微管蚜越冬卵分布部位,采集虫卵及各蚜型成虫,室内镜检并描述其形态特征;2022年3—6月,在金银花田按五点取样法选取植株,定期调查各蚜型数量,采用最优分割法划分胡萝卜微管蚜种群动态并分析其与金银花物候的关系。结果:胡萝卜微管蚜虫卵主要分布在金银花植株的芽鳞、树杈和树皮缝等部位。胡萝卜微管蚜春季在金银花上依次发生干母、无翅孤雌蚜和有翅孤雌蚜3个蚜型,其中干母主要发生于3月9日至4月7日,高峰虫量为29.4只/梢;无翅孤雌蚜和有翅孤雌蚜在3月28日至5月27日混合发生,分别于4月19日和5月13日到达高峰,峰值分别为75.5只/梢和105.6只/梢。胡萝卜微管蚜种群动态与金银花物候特征密切相关,在金银花萌芽展叶期,蚜虫种群处于初建期和缓慢增长期,种群数量低,最高虫量为29.4只/梢;金银花抽梢期,蚜虫种群处于快速增长期,数量迅速上升;金银花花蕾期,蚜虫种群处于高峰期,数量达到高峰值,为370.5只/梢;在金银花开花期,蚜虫种群处于衰退期,数量迅速下降,至6月初基本消失。结论:金银花越冬期是防控胡萝卜微管蚜虫卵的关键期,萌芽展叶期是防控该蚜虫春季种群爆发的关键期。

氮素水平对籼粳杂交稻产量和贮藏蛋白的影响

氮素对稻米蛋白质含量的影响研究颇广,但籼粳杂交稻强弱势粒蛋白组分的积累动态、蛋白质分布及其对氮素的响应鲜有报道。以两个籼粳杂交稻(甬优12和甬优17)为材料,设置4个氮肥水平,即N0(不施氮)、低氮(100 kg·hm^(-2))、中氮(200 kg·hm^(-2))和高氮(300 kg·hm^(-2)),比较了产量、粒型、强弱势粒干物质积累与贮藏蛋白的积累特征。结果显示,施氮显著提高两品种的产量以及蛋白质含量,但品种间对氮素响应存在差异。甬优12在低氮下就能获得较高产量,且其蛋白质积累对氮素响应也较稳定,能实现高产优质的平衡。低氮对粒型无显著影响,高氮显著降低长宽比,导致粒重轻微下降。醇溶蛋白和谷蛋白积累过程存在此起彼伏的现象,从而维持总蛋白的相对平衡。弱势粒蛋白质含量高于强势粒,但因其粒重小导致总积累量仍然低于强势粒。贮藏蛋白主要富集在籽粒外层胚乳中,甬优17对氮素响应较甬优12更敏感。研究结果可为籼粳杂交稻的高产优质栽培技术提供理论依据。

Higher leaf area through leaf width and lower leaf angle were the primary morphological traits for yield advantage of japonica/indica hybrids

The yield potential of japonica/indica hybrids(JIH)has been achieved over 13.5 t ha–1 in large-scale rice fields,and some physiological traits for yield advantage of JIH over japonica inbred rice(JI)and indica hybrid rice(IH)were also identified.To date,little attention has been paid to morphological traits for yield advantage of JIH over JI and IH.For this reason,three JIH,three JI,and three IH were field-grown at East China(Ningbo,Zhejiang Province)in 2015 and 2016.Compared with JI and IH,JIH had 14.3 and 20.8%higher grain yield,respectively,attributed to its more spikelets per panicle and relatively high percentage of filled grains.The advantage in spikelets per panicle of JIH over JI and IH was shown in number of grains on the upper,middle,and lower branches.Compared with JI and IH,JIH had higher leaf area through leaf width and lower leaf angle of upper three leaves,higher leaf area index and leaf area per tiller at heading and maturity stages,higher stem weight per tiller and K and Si concentrations of stem at maturity,higher dry matter weight in leaf,stem,and panicle at heading and maturity stages,and higher biomass accumulation after heading and lower biomass translocation from stem during ripening.Leaf width of upper three leaves were correlated positively,while leaf angle of upper three leaves were correlated negatively with biomass accumulation after heading,stem weight per tiller,and per unit length.Our results indicated that the grain yield advantage of JIH was ascribed mainly to the more spikelets per panicle and relatively high percentage of filled grains.Higher leaf area through leaf width and more erect leaves were associated with improved biomass accumulation and stem weighing during ripening,and were the primary morphological traits underlying higher grain yield of JIH.

减氮方式对不同穗型粳稻产量和品质的影响

为探究氮肥减施策略对不同穗型粳稻产量和品质的影响,于2020年在江苏里下河地区农业科学研究所实验基地以丰粳3227(大穗型)、淮稻5号(中穗型)和扬辐粳8号(小穗型)为试验材料,设置N1(不施氮肥)、N2(当地常规)、N3(基肥减总氮10%)、N4(分蘖肥减总氮10%)、N5(促花肥减总氮10%)、N6(保花肥减总氮10%)、N7(基肥减总氮20%)、N8(分蘖肥减总氮20%)、N9(促花肥减总氮20%)、N10(保花肥减总氮20%)、N11(均衡减总氮10%)、N12(均衡减总氮20%)共12个处理,对不同品种不同处理粳稻的产量和品质进行比较分析。结果表明:大穗型品种丰粳3227在N5处理下、中穗型品种淮稻5号在N11处理下、小穗型品种扬辐粳8号在N6处理下能保持较高的产量,且均与N2处理差异不显著,而其他处理产量均显著低于N2处理。与N2相比,3个品种在上述处理下的茎蘖成穗率、粒叶比、光合势和干物质积累量并未显著降低,且其加工品质、外观品质以及营养与蒸煮食味品质均显著提高。综合来看,针对不同穗型粳稻的氮肥适量减施策略可以改善水稻群体生长和提高稻米品质,在保持高产的同时实现优质。

不同产量水平寒地早粳稻品种的株型特征

为探明寒地早粳稻超高产株型特征,选用700~800 kg/667 m^(2)、600~700 kg/667 m^(2)、500~600 kg/667 m^(2)和400~500 kg/667 m^(2)4个产量水平的48个主栽品种和苗头品系,研究其穗型、叶片和茎秆特征的差异。结果表明,700~800 kg/667 m^(2)水平的早粳稻每穗干质量和着粒密度较高,剑叶、倒2叶和倒3叶叶基角及剑叶披垂度大,后4片叶的叶长序表现为倒2>倒3>倒4>剑叶,剑叶、倒2叶、倒3叶和倒4叶较宽,在合理范围内增加株高,但必须缩短倒4节间长度。相关分析表明,产量与每穗干质量、剑叶和倒2叶叶宽、倒3叶叶长和叶宽、倒4叶叶长和叶宽呈极显著正相关,与秆长、抽穗期和蜡熟期株高呈显著正相关。

高邮龙虬庄遗址的原始稻作

1993～1994年间.曾对高邮龙虬庄遗址进行了考古发掘,在探方T3830中属新石器时期的五个文化层中,有四个文化层淘洗出炭化稻米4000余粒。本研究从炭化稻米的粒型及探方T3929剖面土样中水稻植物蛋白石的形态两个方面,对该遗址新石器时期的原始稻作进行了试探性分析。结果发现:(1)在原始稻作之初,粒型的变异是随栽培化的进展而增大的。(2)在该遗址的新石器时期早期,稻米的进化是缓慢的,在距今6300年至5500年之间,进化有一次飞跃,有意识的人工选择已产生效应。(3)从水稻植物蛋白石的形状分析来看,该遗址出土的炭化稻应当是粳型稻。

北方粳型稻超高产育种理论与实践

从育种理论、育种技术及育种实践等方面,综合评述了中国北方粳型稻超高产育种研究进展与前景,认为培育和推广超级稻是继株型育种和杂交稻之后,提高北方粳稻综合生产能力,实现北方水稻生产跨越式发展的重要途径。在“利用籼粳稻杂交创造新株型和强优势,通过复交优化性状组配,聚合有利基因,选育理想株型与优势利用相结合的超级稻”育种理论与技术路线确立之后,北方粳型超级粳稻在常规育种方面已取得重大突破,成功地培育出一批优质抗病的超级稻新品种并已广泛应用于生产,如沈农265、沈农606、吉粳88等。与常规超级稻育种相比,超级杂交粳稻育种研究进展则相对较缓慢。这一方面是由于北方气候与生态条件的限制,另一方面是育种技术相对落后。解决优势与生育期的矛盾、产量与品质的矛盾以及提高制种产量等问题,仍然是北方超级杂交粳稻育种所面临的严峻挑战。本文还讨论了与粳型超级稻育种有关的生理和遗传问题。

播期和地点对不同生态类型粳稻稻米品质性状的影响

以不同生态类型的5个粳稻品种为材料,在江苏省选择5个不同纬度地点,通过分期播种试验研究稻米品质性状的差异,探讨不同地点和不同播期对稻米加工、外观、蒸煮食味和营养品质的影响。结果表明,13个品质性状在地点、播期及品种间的差异均达到了极显著水平,多数性状品种间变异最大,地点次之,播期影响最小。不同品质性状在不同纬度的变化趋势不同,稻米加工品质随纬度的升高呈改善趋势,粒长、粒宽和长宽比在不同纬度间的变化较小,直链淀粉含量、糊化温度、胶稠度和食味值呈北高南低的趋势,垩白率、垩白度和蛋白质含量则呈现南高北低的趋势,食味品质随纬度的升高有提高趋势。随播期的推迟,加工品质、直链淀粉含量、糊化温度、蛋白质含量均有提高的趋势,粒长和长宽比增加,粒宽减小,胶稠度降低,垩白率和垩白度在不同播期之间存在显著差异,但变幅不大,过早或过迟播种食味值均有降低趋势。不同性状对地点和播期的反应不同,糙米率、粒宽、粒长、长宽比和精米率受影响较小,而垩白率和垩白度受影响较大,整精米率、糊化温度、蛋白质含量、直链淀粉含量、胶稠度和食味值居两者之间。不同品种不同品质性状在地点和播期间的稳定性不同,南粳46的品质性状综合表现最好,但受地点和播期的影响较大。

杂交粳稻超高产栽培技术的研究

以杂交粳稻新组合“榆杂２９”两年的超高产实践为研究内容，探讨该组合超高产的技术路线和主要的栽培技术措施．研究表明：１“榆杂２９”的超高产技术路线有两条．２超高产需要肥沃的水稻土和科学的施肥、管理技术．３超高产的群体最大叶面积指数仍在孕穗期，达９．２６～９．５８４超高产的关键措施：培育壮秧，适时早栽、施足促蘖肥，及时促控、增施钾肥、磷肥、保健栽培．

粳型光敏核不育系选育与应用初报

１９８０年以农垦５８Ｓ为光敏核不育基因供体，与国内外粳稻品种（系）杂交，经多代连续选择，育成一批具有不育性稳定、育性转换明显、开花习性好、易繁殖制种、抗病性较强、配组优势明显的模型光敏核不育系。用其配制的组合Ｎ５０４７Ｓ／Ｒ９－１和Ｎ５０８８Ｓ／Ｒ９－１等，１９９２年示范面积达３万余亩，并获得初步成功。