杂交早稻吸氮特性与产量形成的初步研究

研究了在不同施氮水平下,杂交早稻吸氮特性及其与产量形成的关系。结果表明;杂交早稻威优49亩产500千克左右,植株每亩总吸氮量平均为9.78千克,其中土壤供氮量占52.45%。杂交早稻一生中前期吸氮量占50.72%,中期占31.08%,后期占18.30%,以中期施氮对叶片含氮率影响最大。在高氮水平下,中期施氮导致茎鞘醣含量急剧下降。抽穗前植株吸氮量与每亩发育颖花数呈极显著正相关,但结实率受每朵颖花占有抽穗前醣量的影响。最适 LAI 为6.5～7.5。     

内源IAA对杂交稻强、弱势粒灌浆增重的影响

以超级杂交稻协优9308和杂交稻协优9312、Ⅱ优162及其相应恢复系为材料,对灌浆初期籽粒中内源IAA、糖分的变化,以及IAA抑制剂对IAA以及3H 标记葡萄糖吸收分配和籽粒灌浆的影响进行了研究。结果表明在籽粒灌浆初期强势粒的IAA含量以及增重的速度始终高于弱势粒。在开花受精7 d以前,强势粒中果糖、葡萄糖及蔗糖的含量高于弱势粒,之后相反。强、弱势粒间存在的这种灌浆势差异,杂交组合大于其相应的恢复系。IAA合成及运输抑制剂明显降低3H 葡萄糖在籽粒中的分配。外源IAA对幼穗的处理,缩小了强、弱势粒间结实率的差异,使整穗的结实率也有所提高。     

Relationship between Dry Weight at Heading and the Number ofSpikelets on Individual Rice Tillers

Abstract

The objectives of this study were to identify the growth parameters involved in determining the number of spikelets on an individual tiller (ST) and to elucidate how ST is determined in rice (Oryza sativa L.). We examined the correlation of ST with the dry weight (DWT), leaf area (LAT), and the amount of nitrogen (NT) at heading for individual tillers grown under different conditions that were expected to affect spikelet production. In 1999, the japonica rice cultivars “Mineasahi” (short-duration), “Hinohikari” (intermediate-duration), and “Akebono” (long-duration) were transplanted in a paddy field on two different dates (EARLY and LATE). In 2000, Hinohikari was grown under three different treatments (gibberellic acid application, nitrogen topdressing, and thinning of hills at panicle initiation) and without treatment (control). Covariance and partial correlation analyses indicated that ST was positively and essentially correlated with DWT rather than with LAT and NT. The regression of ST on DWT was stable within each cultivar regardless of the treatment, year, tiller order, and number of differentiated spikelets. The slope of the regression was the steepest in the short-duration cultivar. These results suggest that the steep slope is desirable for high-yielding cultivars with large panicles. We conclude that ST is mostly determined by dry matter production of an individual tiller regardless of the number of differentiated spikelets. We present a diagram showing the relationship between dry matter production and the number of differentiated, surviving, and degenerated spikelets on an individual tiller.     

A Simple Device to Prepare Single Ears of Spelt (Triticum spelta L.) for Seeding with the "Seedmatic-System"

Spelt is usually planted as spikelets. These cannot be obtained by the threshing machines generally used for bread wheat. With a simple device it is possible to separate single ears of spelt into spikelets ready for sowing. At the same time, it is possible to score the fragility of the rachis and the degree of free thresh-ability, both important characteristics for the selection of spelt.     

A reciprocal F1 monosomic analysis of the genetic control of time of ear emergence,number of leaves and number of spikelets in wheat (Triticum aestivum L.)

Summary A reciprocal F₁ monosomic analysis of chromosomal differences between Spica and Bersée was carried out under controlled environment conditions. Chromosomes associated with differences in days to ear emergence, number of leaves and number of spikelets were identified. The results indicated that chromosome 2B of Spica carries a photoperiod insensitivity allele at the Ppd ₂ locus. Both Spica and Bersée appear to have a vernalization insensitity allele at the Vrn ₂ locus on chromosome 5B. On chromosome 3A, 4B, 4D and 6B factors were found with major effects on earliness per se, diffeences in ear emergence and number of spikelets which were independent of photoperiod and vernalization. The possibility that these factors influence growth rate is discussed.     

水稻簇生穗突变体的鉴定及遗传

对回交转育的簇生穗品系CL－802、自然簇生穗突变体麦疑稻、人工诱导簇生穗突变体双科早系列和中花11系列进行观察和比较，发现人工诱导产生的簇生穗突变体具有粒长变短、长宽比变小的特点，而自然簇生穗突变体不存在这种现象，以簇生穗突变体麦颖稻为亲本，与正常穗型水稻品种杂交所得的F1代、F2代进行系统分析，结果表明，F1代表现簇生但簇生程度较亲本麦颖稻轻，为中间类型；F2代产生簇生型、中间型和正常型的分离，组合分离比有些符合1：2：1，有些不符，其正常穗型的比例在30％－40％之间。麦颖稻的簇生穗性状表现为部分显性。     

两系杂交稻“两优培九”的选育及其栽培特性

 采用两系方法以培矮 6 4S作母本 ,9311作父本 ,培育的籼型杂交稻两优培九 ,作一季中稻栽培 ,在掌握栽培特性和肥水良好的条件下 ,大面积实收产量达 9.5～ 11.0t·ha-1,且不易倒伏。米质达国标优质米级 ,并抗白叶枯病和稻瘟病。高产群体指标为每公顷栽插 2 2 .5～ 2 7.0万穴。单株栽插 ,基本苗 75～ 12 0万个·ha-1,最高茎蘖数345 .0～ 375 .0万个·ha-1,有效穗 2 2 5 .0～ 2 5 5 .0万穗·ha-1,每穗总颖花 2 0 0个左右 ,结实率 83%～ 88% ,千粒重 2 6～2 7g。栽培技术为适时早播 ,早施分蘖肥 ,达到前期早发中期稳长。基面肥、分蘖肥与后期施氮量各占总施氮量的70 %和 30 % ,每公顷总用纯氮量 2 2 5～ 2 5 5kg。宜重视磷钾肥的施用 ,后期切忌早断水 ,应切实防治稻曲病。     

春小麦幼苗期适宜土壤湿度及其需水量与小穗数的数学模型

本文通过正交试验,建立春小麦苗期需水量与每穗小麦小穗数的相关关系,进而可以按预定的小麦产量,推算出其适宜的灌水量,以达到提高灌水经济效益的目的。     

水稻粒穗分离力的研究

为揭示当前条件下水稻粒穗分离力的现状，用传感器计算机数据采集与分析系统，对南方常见的几种水稻品种的粒穗分离力进行了测试．结果表明，不同收获时期粒穗分离力各品种间有明显差异．不同品种的稻谷含水量不同，粒穗分离力亦不同，脱粒的难易程度也会发生变化．含水量越高越容易脱粒，但有些品种含水量达到一定值后粒穗分离力会变大．成熟度是影响粒穗分离力的重要因素，成熟度高，粒穗分离力小．