Relationship Between Heterosis and Parental Genetic Distance Based on Molecular Markers for Functional Genes Related to Yield Traits in Rice

The genetic distances among 18 cytoplasmic male sterile lines and 11 restorer lines were analyzed with molecular markers derived from yield-related functional genes. The correlation between parental genetic distance and heterosis was investigated by analyzing the performance of 47 combinations. The results showed that the genetic distance was significantly correlated with yield heterosis （r=0.29^＊）, but not significantly correlated with heterosis for other traits, such as number of effective panicles per plant, seed setting rate, 1000-grain weight, number of grains per panicle and theoretical yield. However, the correlation coefficient was so small that the parental genetic distance could not to be used to predict heterosis.

Dissection of heterosis for yield and related traits using populations derived from introgression lines in rice

Despite the great success achieved by the exploitation of heterosis in rice,the genetic basis of heterosis is still not well understood.We adopted an advanced-backcross breeding strategy to dissect the genetic basis of heterosis for yield and eight related traits.Four testcross(TC) populations with 228 testcross F1 combinations were developed by crossing57 introgression lines with four types of widely used male sterile lines using a North Carolina II mating design.Analysis of variance indicated that the effects of testcross F1 combinations and their parents were significant or highly significant for most of the traits in both years,and all interaction effects with year were significant for most of the traits.Positive midparent heterosis(HMP) was observed for most traits in the four TC populations in the two years.The relative HMPlevels for most traits varied from highly negative to highly positive.Sixty-two dominant-effect QTL were identified for HMPof the nine traits in the four TC populations in the two years.Of these,22 QTL were also identified for the performance of testcross F1.Most dominant-effect QTL could individually explain more than 10% of the phenotypic variation.Four QTL clusters were observed including the region surrounding the RM9–RM297 region on chromosome 1,the RM110–RM279–RM8–RM5699–RM452 region on chromosome 2,the RM5463 locus on chromosome 6 and the RM1146–RM147 region on chromosome 10.The identified QTL for heterosis provide valuable information for dissecting the genetic basis of heterosis.

Interactive Effects of Silicon and Potassium Nitrate in Improving Salt Tolerance of Wheat

Adequate regulation of mineral nutrients might be effective to ameliorate the deleterious effects of salts and help to sustain crop productivity, particularly in glycophytes, under salt stress. In this study, laboratory and greenhouse experiments were carried out at Agricultural and Natural Resources Research Centre in East Azerbaijan, Iran, to investigate the interactive effects of silicon and potassium nitrate in alleviating NaCl induced injuries in wheat（Triticum aestivum L.）. In the laboratory experiment, three winter wheat cultivars Pishgam, Afagh and Alvand were grown on sterile filter paper moistened with 20, 40, 60, 80, and 100 mmol L-1 NaCl solution. Results revealed that wheat cultivars were significantly different in their growth response to different concentrations of NaCl and Pishgam was found to be the most tolerant to NaCl stress, and used in the second part of study. In the greenhouse experiment, Pishgam was grown in a hydroponic system subjected to different NaCl levels（20, 60 and 100 mmol L-1） and treated by silicon（0, 2 and 4 mmol L-1, final concentration in nutrient solution using K2SiO3） and potassium nitrate（0, 0.5, 1, and 2 mmol L-1, foliar application）. The experimental design was factorial based on a completely randomized design with three replications. It was found that NaCl stress significantly increased proline accumulation and sodium content in the plant tissues while decreased potassium uptake and accumulation by plants. Moreover, plant weight, 100-seed weight, relative water content, chlorophyll content, and photosynthesis were also significantly affected by varying levels of NaCl. However, exogenous application of silicon and potassium nitrate reduced sodium uptake, increased potassium and consequently improved plant weight, 100-seed weight, seed yield, ear length, and photosynthesis rate. This study suggested that utilization of the salt-tolerant cultivar（Pishgam） combined with proper foliar application of potassium nitrate（2 mmol L-1） and silicon（4 mmol L-1） at the wheat booting stage might be a promising approach to obtain higher grain yield on saline lands.

Technology Relating to Catalyst for Boosting Gasoline Yield Developed by RIPP Passed Appraisal

Currently the project'Development and commercia application of FCC catalyst for boosting gasoline yield'jointly undertaken by the SINOPEC Research Institute of Petroleum Processing(RIPP),the SINOPEC Yanshan Branch Co.and the Branch of SINOPEC Catalyst Company has passed the appraisal.The catalyst aimed at boosting

Root morphological traits and their relations with yield components of dry-raised mid-season indica rice

Research on root morphological traits of dry-raised seedlings (D-RS) at different growth stages of rice have so far attracted less attention. In this study, using mid-season indica hy-

Attribution of Maize Yield Increase in China to Climate Change and Technological Advancement Between 1980 and 2010

Crop yields are affected by climate change and technological advancement.Objectively and quantitatively evaluating the attribution of crop yield change to climate change and technological advancement will ensure sustainable development of agriculture under climate change.In this study,daily climate variables obtained from 553 meteorological stations in China for the period 1961-2010,detailed observations of maize from 653 agricultural meteorological stations for the period 1981-2010,and results using an Agro-Ecological Zones（AEZ） model,are used to explore the attribution of maize（Zea mays L.） yield change to climate change and technological advancement.In the AEZ model,the climatic potential productivity is examined through three step-by-step levels：photosynthetic potential productivity,photosynthetic thermal potential productivity,and climatic potential productivity.The relative impacts of different climate variables on climatic potential productivity of maize from 1961 to 2010 in China are then evaluated.Combined with the observations of maize,the contributions of climate change and technological advancement to maize yield from 1981 to 2010 in China are separated.The results show that,from 1961 to 2010,climate change had a significant adverse impact on the climatic potential productivity of maize in China.Decreased radiation and increased temperature were the main factors leading to the decrease of climatic potential productivity.However,changes in precipitation had only a small effect.The maize yields of the 14 main planting provinces in China increased obviously over the past 30 years,which was opposite to the decreasing trends of climatic potential productivity.This suggests that technological advancement has offset the negative effects of climate change on maize yield.Technological advancement contributed to maize yield increases by 99.6%-141.6%,while climate change contribution was from-41.4%to 0.4%.In particular,the actual maize yields in Shandong,Henan,Jilin,and Inner Mongolia increased by 98.4,90.4,98.7,and 121.5 kg hm^（-2） yr^（-1） over the past 30 years,respectively.Correspondingly,the maize yields affected by technological advancement increased by 113.7,97.9,111.5,and 124.8 kg hm^（-2） yr^（-1）,respectively.On the contrary,maize yields reduced markedly under climate change,with an average reduction of-9.0 kg hm^（-2） yr^（-1）.Our findings highlight that agronomic technological advancement has contributed dominantly to maize yield increases in China in the past three decades.

Arbuscular mycorrhizal impacts on competitive interactions between Acacia etbaica and Boswellia papyrifera seedlings under drought stress

Aims Arbuscular mycorrhizal fungi can have a substantial effect on the water and nutrient uptake by plants and the competition between plants in harsh environments where resource availability comes in pulses.In this study we focus on interspecific competition between Acaia etbaica and Boswellia papyrifera that have distinctive resource acquisition strategies.We compared the extent of interspecific competition with that of intraspecific competition.Methods In a greenhouse study we examined the influence of Arbuscular Mycorrhiza(AM)and pulsed water availability on competitive interactions between seedlings of the rapidly growing species A.etbaica and the slowly growing species B.papyrifera.A factorial experimental design was used.The factors were AM,two water levels and five species combinations Important Findings Seedlings of both species benefitted from AM when grown alone,and the positive growth response to pulsed water availability in B.papyrifera seedlings was in contrast with the negative growth response for A.etbaica seedlings.AM also affected the competitive performance of both species.B.papyrifera was not affected by intraspecific competition,whereas A.etbaica was negatively affected compared to the seedlings grown alone.This effect was stronger in the presence of AM.In interspecific competition,A.etbaica outcompeted B.papyrifera.Mycorrhiza and pulsed water availability did not affect the outcome of interspecific competition,and the aggressivity index of A.etbaica remained unchanged.The extent to which AM influences plant competition in a droughtstressed environment may depend on belowground functional traits of the species.AM and pulsed water availability could modify the balance between intraspecific and interspecific competition.By affecting the balance between intraspecific and interspecific competition,both factors could impact the establishment and survival of seedlings.

Luminescence of coelenterazine derivatives with C-8 extended electronic conjugation

Replacement of the methylene group at the C-8 position with an extended electronic conjugation is a new promising method to develop red-shifted coelenterazine derivatives. In this paper, we have described an oxygen-containing coelenterazine derivative with a significant red-shifted（63 nm）bioluminescence signal maximum relative to coelenterazine 400a（Deep Blue C^（TM）, 1）. In cell imaging, the sulfur-containing coelenterazine derivative displayed a significantly（1.77 ± 0.09;P≤0.01） higher luminescence signal compared to coelenterazine 400 a and the oxygen-containing coelenterazine derivative exhibited a slightly（0.74 ± 0.08; P≤0.05） lower luminescence signal. It is beneficial to understand further the underlying mechanisms of bioluminescence.

Increasing yield potential through manipulating of an ARE1 ortholog related to nitrogen use efficiency in wheat by CRISPR/Cas9

Wheat(Triticum aestivum L.)is a staple food crop consumed by more than 30%of world population.Nitrogen(N)fertilizer has been applied broadly in agriculture practice to improve wheat yield to meet the growing demands for food production.However,undue N fertilizer application and the low N use efficiency(NUE)of modern wheat varieties are aggravating environmental pollution and ecological deterioration.Under nitrogen-limiting conditions,the rice(Oryza sativa)abnormal cytokinin response1 repressor1(are1)mutant exhibits increased NUE,delayed senescence and consequently,increased grain yield.However,the function of ARE1 ortholog in wheat remains unknown.Here,we isolated and characterized three TaARE1 homoeologs from the elite Chinese winter wheat cultivar ZhengMai 7698.We then used CRISPR/Cas9-mediated targeted mutagenesis to generate a series of transgene-free mutant lines either with partial or triple-null taare1 alleles.All transgene-free mutant lines showed enhanced tolerance to N starvation,and showed delayed senescence and increased grain yield in field conditions.In particular,the AABBdd and aabbDD mutant lines exhibited delayed senescence and significantly increased grain yield without growth defects compared to the wild-type control.Together,our results underscore the potential to manipulate ARE1 orthologs through gene editing for breeding of high-yield wheat as well as other cereal crops with improved NUE.