High-yield Cultivation Technique of Salt-tolerant Spartina and Rice in Coastal Mudflat

Directing at the characteristics of coastal mudfiat saline and alkaline land, the yield of salt-tolerant Spartina and rice could reach 5 925-8 280 kg/hm^2 by the techniques of land and water resource utilization, farming improvement, construction of matched water system, seed selection and treatment, water direct seeding, seedling raising on seedbed, field transplanting, weeding, nutrient and water management, and disease and pest control, providing a scientific basis for the cultivation of Spartina and Rice in coast mudflat.

Innovation on Distant Hybridization of Saline-tolerant Mud Flat Spartina and Rice Germplasm

To explore saline-tolerant high yield Spartina and rice germplasm resources,innovate upon distant hybridization technology,and develop new saline-tolerant mud flat Spartina germplasm,autonomous patent for invention was used to study distant hybridization of Spartina and rice in 2005- 2016. The study adopted tidal flat planting screening,phenotypic screening,molecular marker assisted selection,to find biological evidences of new germplasm,and also applied crossbreeding,conventional breeding,and molecular breeding,to select new saline-tolerant Spartina and rice varieties. With 12 years of efforts,the team developed 1498 crossbreeding combinations and established pedigree file and seed bank,tested 307 crossbreeding materials(57 hybrid seeds showed parental genetic components of Spartina and Rice); obtained Spartina/ Rice distant hybridization and seed setting,transplanting,hybridization material economic traits,and molecular biological experimental evidences; Rice♀× Spartina ♂ hybridization success rate of 1. 04- 1. 39%; obtained authorization of patent for invention of Distant Hybridization Methods for Spartina and Rice; formulated procedures for high yield cultivation of Spartina-Rice,planted 33. 33 hm2Spartina-Rice in coastal saline and alkaline land,cultivated 10 new saline-tolerant Spartina-Rice varieties,and the rice yield up to 5. 925- 8. 28 t / hm2. Results indicate that Spartina-Rice is saline-tolerant high yield rice germplasm,developed through sexual hybridization,conventional breeding,and molecular breeding technologies,and is optimal crop for saline and alkaline land. Success of Spartina-Rice solves the problem of saline-tolerant crop badly for transformation of saline and alkaline land,the problem of feeds for herbivores,as well as problem of environmental pollution resulted from straw burning. Besides,it is of essential scientific significance for resource utilization,increase of agricultural efficiency,grain security,and farmland strategy,so it has broad application prospect.

An Innovative Strategy for Reciprocal Distant Hybridization between Spartina alterniflora and Rice

[Objective] This study aimed to explore germplasm resources of salt toler- ant Spartina alterniflora and high yield rice, and develop an innovative strategy for distant hybridization between S. altemiflora and rice. [Method] Crossing （rice ♀ ）： hot water emasculation and glume-cutting pollination method, heat emasculation and pollen-suction pollination method; reciprocal crossing （S. alterniflora ♀ glume-cutting emasculation and pollination method, continuous emasculation-pollination method, hot water emasculation and continuous emasculation-pollination method. [Result] In crossing groups （rice ♀ × S. alterniflora ♂ ）, compared with hot water emasculation and glume-cutting pollination treatment, the number of seed-bearing combinations, seed number per spike and seedling emergence rate in heat emasculation and pollen-suction pollination treatment were improved by 34.09%, 121.21% and 60.07%, respectively; hybridization efficiency was improved by 6-7 times. In reciprocal cross- ing groups （S. altemiflora ♀× rice ♂ ）, compared with glume-cutting emasculation and pollination treatment, the number of seed-bearing combinations and seed num- ber per spike in continuous emasculation-pollination treatment were improved by 3.14 and 4.21 times, respectively; seedling emergence rate was improved by 68.47%; hybridization efficiency was improved by 7-8 times. [Conclusion] Heat emas- culation and pollen-suction pollination method is suitable for hybridization between rice ♀× S. alterniflora ♂; continuous emasculation-pollination method is suitable for hybridization between S. alterniflora ♀× rice ♂.

Differential gene expression in salt-tolerant rice mutant and its parental variety

The differential expressions of three genes rbcL, salT and rab!6 in response to ABA, NaCl, PEG and heat shock were investigated in seedlings of a salt-tolerant rice mutant 20 (mutant 20) and its parental variety Oryza sativa var. japonica 77-170(170). By Northern blot analysis it was found that ABA induced the expression of all three genes of rbcL, salT and rab16 in shoots and roots of both 170 and mutant 20 with the exceptions of rab16 in shoots of mutant 20 and rbcL in roots of 170. Lower concentrations of NaCl induced rbcL expression in shoots of mutant 20 but not 170. Higher concentrations of NaCl decreased rbcL expression but induced expressions of salT and rab16 in shoots of both 170 and mutant 20. PEG(15%) and 37℃ heat shock showed almost no effects on the expression of the three genes in mutant 20. However, they caused a decrease in rbcL expression and slight induction of the rab16 gene in 170, with salT expression unaffected. These results indicated that mutant 20 was relatively less responsive to applied hormonal and environmental factors as compared with 170, suggesting that mutant 20 might have acquired mechanisms by which the plant is less responsive to environmental stresses and hence gain a stronger ability to tolerate stresses.

Analysis of genes specifically expressed under salt stress in salt-tolerant mutant of rice by using DDRT-PCR technique

Differential display reverse transcription-PCR (DDRT-PCR) technique was used to identify those genes that are expressed differentially between wild type rice variety 77-170 (Oryza Sativa vas Japonica) and its salt-tolerant mutant (M-20) under salt stress. Totally 13 salt-inducible cDNA fragments of 200-600 bp were identified and doned, and were designated as SIGR1 - SIGR13 (salt-induced gene in rice). Northern blot analysis showed that expression of SIGR6 and SIGR8 was salt-inducible in both wild type and mutant, and expression of SIGR12 in M-20 was much higher than that in 77-170 under salt stress. It was also shown that expression of SIGR3, SIGR4, SIGR7, SIGRIO and SIGR13 was salt-inducible, and the genes were highly homologous with Rab1d which was an ABA-inducible gene of rice. The great potential application of DDRT-PCR technique in plant molecular biology research may promote the investigation of expression of salt-induced protein in rice.

海涂米草与水稻远缘杂交种质资源发掘与创新

米草具有耐盐、耐淹等优良特性;水稻籽粒饱满,产量高。本研究通过米草与水稻远缘杂交,试图选育耐盐高产的米草/水稻粮饲兼用作物新品种。2005-2006年,引种栽培了大米草1720株,水稻品种（组合）15种,进行了大米草与水稻杂交试验。结果表明：2005年,水稻培矮64S/04141（♀）与大米草（♂）杂交结籽149粒。2006年,F1代自交结种224穗,获自交种籽11842粒,千粒重18.39g;F1（♀）×大米草（♂）回交17穗,获BC1F1种籽24粒,回交结实率2.84%;水稻（♀）×大米草（♂）杂交6个品种（组合）23穗,获种籽63粒,杂交结实率4.2%。大米草与水稻杂交,其RAPD反应表明,杂交后代与水稻亲本相比,条带有明显差别,表明远缘杂交导致水稻发生了基因重组。2005年,引种栽培了互花米草560株,2006年进行了互花米草与水稻杂交试验。结果表明：水稻（♀）7个品种（组合）×互花米草（♂）杂交39穗,得杂交种籽115粒,杂交穗结籽率5.4%;F132、F134（♀）×互花米草（♂）杂交12穗,得杂交种籽18粒,杂交穗结籽率2%。2007年在启东协兴港海涂滩地米草稻田大米草/水稻F2在土壤含盐量7.83‰,pH8.20,灌溉水10.37‰情况下,千粒重达18g,结实率52.8%,单株种籽重19.97g;在如东羊场米草稻田大米草/水稻F2在土壤含盐量5.28‰,pH7.9情况下,千粒重达22g,结实率51.1%,单株种籽重19.1g。水稻×玉米×米草三元杂交种籽千粒重22.8g,结实率69.9%,单株种籽重41.4g;在农科所试验地大米草/水稻F2代千粒重22.4g,结实率58.2%,单株种籽重33.7g;水稻×玉米×米草三元杂交种籽千粒重25.2g,结实率82%,单株种籽重59.2g。

大米草与水稻远缘杂交试验初报

2005—2006年,引种栽培大米草1720株,栽培水稻品种(组合)20种,进行了大米草与水稻远缘杂交试验。结果表明:2005年,大米草(♂)与水稻培矮64S/04141(组合,♀)杂交结籽149粒。2006年,F1代自交结种224穗,获自交种子11842粒,千粒重18.39 g;大米草(♂)×F1(♀)杂交17穗,获种子24粒,杂交结实率2.84%;大米草(♂)×水稻(♀)杂交6个品种(组合)23穗,获种子63粒,杂交结实率4.2%。水稻与大米草远缘杂交后代变异的RAPD分析表明:杂交后代与水稻亲本相比,条带有明显差别,说明远缘杂交导致了水稻发生基因重组。

过量表达SaSOS1水稻的幼苗鉴定及生理特性分析

为研究泌盐盐生植物互花米草(Spartina alterniflora)SOS1基因的功能及抗逆机制,对过量表达Sa SOS1的T3代纯合转基因水稻株系幼苗进行了鉴定及生理特性分析。分子鉴定和表型鉴定显示,转基因株系13-4、15-6、16-1、16-2、19-4、19-6为阳性转基因株系,其中13-4、16-2株系在250 mmol/L Na Cl处理下表现出更强的耐盐性。生理特性分析表明,与野生型日本晴株系相比,转基因株系13-4、16-2植株叶片含水量较高,可溶性糖含量较高,并维持了较低的MDA含量和电导率。说明转基因株系能有效减少盐胁迫伤害,保持较好的生长状态。

Identification of salt-tolerance QTL in rice(Oryza sativa L.)

Quantitative trait loci (QTLs) controlling salt-tolerance at the seedling stage in rice (Oryza sativa L.) were identified by interval mapping (SIM) and composite interval mapping (CIM) using a doubled haploid population ZJDH and its high resolution genetic linkage map. The population was derived from an inter-subspecific cross between an indica variety Zhaiyeqing8 (ZYQ8) and a japonica variety Jingxi17 (JX17). Analysis of survival days of seedlings treated with 0.7% NaCl revealed that a major salt-tolerance quantitative trait locus (QTL), Std, was present between markers RG612 and C131 on chromosome 1 when using both MAPMAKER/QTL 1.1 and PLABQTL 1.0 (SIM).Its allele which contributes to salt-tolerance was from ZYQ8. In addition, seven more QTLs which give additive effect on salt-tolerance are identified when using PLABQTL(CIM), and most of them were from JX17.

沿海滩涂耐盐米草稻高产栽培技术

从水土资源利用、耕作改良、配套水系建设、种子选择及处理、水直播、苗床育秧、大田移栽、除草、肥水管理、病虫害防治等方面对沿海滩涂耐盐米草稻高产栽培技术进行总结。

海涂大米草与水稻正反远缘杂交创新方法研究

发掘海涂大米草耐盐、水稻高产种质资源，创新大米草与水稻正反远缘杂交适用方法。本文研究了正交法（水稻♀温汤杀雄剪颖授粉法、热气杀雄吸花授粉法）和反交法（大米草♀剪颖去雄授粉法、连续去雄授粉法、温汤杀雄连续去雄授粉法）。结果表明，水稻辛热气去雄吸花授粉法比温汤杀雄剪颖授粉法结籽组合数提高103．23％，穗均结籽提高65．58％，出苗率提高88．67％，提高工效5～6倍；大米草♀连续去雄授粉法比剪颖去雄授粉法结籽组合数增加1．67倍，穗均结籽增加2．83倍，出苗率提高41．79％，提高工效6～7倍。水稻早热气去雄吸花授粉杂交法适用于水稻♀×大米草♂；大米草♀连续去雄授粉杂交法适用于大米草♀×水稻♂。

利用互花米草和水稻杂交提高水稻耐盐性的研究

选取互花米草与水稻杂交加代后的6个稳定水稻品系分别与其水稻母本在淡水和4‰咸水处理下进行耐盐性试验。结果表明:海粳18号、海粳19、海粳23、海粳25、海粳31的咸水产量损失率显著低于其母本,海粳29的产量损失率低于其母本,但统计学上差异不显著;利用灰色关联度综合评价分析得出在咸水中种植的海粳19、海粳23、海粳25的综合生产性能表现好于其母本,表明利用互花米草与水稻杂交能够提高耐盐性。