Production of Yam Tubers Using Seed Tubers from Vitroplants Regenerated from Aerial Stems in the Yam Species Dioscorea alata (L.) and Dioscorea cayenensis-rotundata (L. & P.) in Côte d’Ivoire

The aim of this study is to produce large quantities of yam tubers in the field from seed tubers derived from vitroplants regenerated from aerial stem cuttings and farmers’ tuber seeds. Seed tubers from ten yam cultivars, including five from Dioscorea alata (cDa083, cDa053, cDa115, cDa150 and cDa266) and five from Dioscorea cayenensis-rotundata (cDr015, cDr027, cDr150, cDr206 and cDr148) with distinct agro-morphological characteristics, were used as material. A completely randomized block design with 3 replications was used. In each block, all cultivars and seed types were represented. When put into cultivation, the tubers produced by the vitroplants all germinated and gave 100% healthy plants, compared with 86% to 100% healthy plants for the seed tubers produced by the farmers. Yields per hectare ranged from 10 to 25 tonnes for seed tubers produced by in vitro plants, and from 4 to 9 tons for seed tubers produced by farmers. Seed tubers from vitroplants can therefore be recommended to farmers as a solution to the problem of seed tuber unavailability.

冬小麦杂种优势表现及分析

用142个普通小麦为亲本配制杂交组合273个,以冬小麦品种石4185为对照,对F1代材料的株高、株穗数、穗长、小穗数、穗粒数和千粒重性状表现进行了分析。结果表明:F1代杂种优势范围为38.7%～124.0%,性状顺序为株穗数>穗粒数>株高>千粒重>穗长>小穗数。千粒重正向杂种优势与负向杂种优势之比为4.39∶1,其次为穗粒数、小穗数、穗长、株穗数和株高。有96.70%的组合千粒重>CK,而小穗数和株穗数的负优势组合数分别占观察总数的71.79%和56.04%。逐步回归分析发现,影响杂种优势的主要因素顺序为株穗数>穗粒数>千粒重>株高,分别达到了极显著和显著水平,决定系数R2=0.99。小麦单一性状杂种优势十分明显,对杂交种开发具有较大的遗传潜力。从应用角度看,株穗数、穗粒数和千粒重均>CK且株高≤CK的组合数仅有14个,只占观察总数的5.13%,比例较小。株穗数、穗粒数、千粒重的正向超标优势分别为64.0%、59.2%和51.8%,位居所有参试性状前3位。在小麦杂交育种中,可根据不同的产量结构如大穗型、大粒型、多穗型进行组合搭配,同时注重显性矮秆基因的利用。

矮秆早熟化学杀雄杂交小麦--母本衡5835

衡5835是河北省农林科学院旱作农业研究所选育的具有自主知识产权的矮秆、大穗、早熟冬小麦新品种,于2018年通过河北省农作物品种审定委员会审定,审定编号为冀审麦20180012,亲本组合为衡8185/石新618//衡观35。衡8185和衡观35为河北农林科学院旱作农业研究所自育品种(系),石新618来自于石家庄市小麦新品种新技术研究所。衡5835在亲本组合组配上,采用了复交(三交)的杂交方式,期望将衡8185的抗病性、石新618的抗旱节水突出特性及衡观35的矮秆、早熟、稳产特性等优良基因聚合。

播期和密度对冬小麦杂交种衡杂102产量及其构成因素的影响

为了明确冬小麦杂交种衡杂102的高产高效栽培技术措施,为该品种大面积应用提供理论依据,2014~2015年在河北省农林科学院旱作农业研究所旱作节水试验站进行了不同播期与密度组合的产量试验。采用裂区试验设计,播期设10月5、10、15、20和25日5个水平,密度(基本苗数量)设150万、225万、300万、375万、450万株/hm^2以及对照(石4185)6个处理,研究了不同播期与密度组合对衡杂102产量以及产量构成因素的影响;并对不同播期与密度组合的产量进行了回归分析,根据回归方程,对10月5~25日播种,在10月5日播种基本苗数量150万株/hm^2的基础上,每晚播1 d、基本苗数量增加15万株/hm^2条件下,进行了产量模拟,以探索适宜的播期及其相应的种植密度。结果表明:播种期和种植密度均对产量以及产量构成因素具有显著影响,其中,产量随着播期的推迟、种植密度的增加呈先升高后降低的趋势。在一定的播期和密度范围内,衡杂102单位面积穗数随着播期的推迟而减少,随着密度的增加而明显增多;穗粒数和千粒重随着播期的推迟而增加,随着密度的增加而降低,其中,播期和密度对千粒重的影响大于对穗粒数的影响。冬小麦新品种衡杂102的适宜播种期为10月5~16日,相应的种植密度为150万~315万株/hm^2,产量模拟结果与实际测定结果相吻合。

Genotype-by-environment interaction for grain yield among novel cowpea(Vigna unguiculata L.) selections derived by gamma irradiation

This study determined the effects of genotype-by-environment(G × E) interaction and stability of yield among elite cowpea(Vigna unguiculata L.) selections derived by gamma irradiation. The study was conducted in Namibia at three selected sites: Bagani, Mannheim,and Omahenene, during 2014/2015 and 2015/2016. Thirty-four newly developed mutant genotypes and three local checks were evaluated using a randomized complete block design with three replications. Grain yield data were analyzed using the additive main effects and multiplicative interaction(AMMI) and the genotype main effect plus genotype-by-environment interaction(GGE) biplot methods. The AMMI and GGE biplot models explained 77.49% and 75.57% of total observed genotypic variation, respectively.Bagani and Omahenene were the environments best discriminating the test genotypes during 2014/2015 and 2015/2016, respectively. Four promising mutant genotypes: G9(Sh L3 P74), G10(Sh R3 P4), G12(Sh R9 P5), and G4(Sh L2 P4), showed wide adaptation and grain yields of 2.83, 2.06, 1.99, and 1.95 t ha^(-1), respectively. The novel mutant lines are useful genetic resources for production or future cowpea breeding programs in Namibia or similar environments.

大豆除草剂豆草除^(TM)诱导旗叶露尖期小麦雄性不育的研究

为给化学杀雄诱导小麦雄性不育研究提供杀雄彻底、成本低廉的新型化学杂交剂,在小麦旗叶露尖期(Feekes 8.0)分别用0(清水,CK)、5.59、11.17和16.75 mg/kg浓度的大豆除草剂豆草除TM进行喷雾,研究该药剂作为杀雄剂诱导小麦雄性不育的效果及其对小麦农艺性状的影响。结果表明:在小麦旗叶露尖期(Feekes 8.0)喷施豆草除TM,能诱导96.79%~99.06%的雄性不育;株高、穗长和小穗数均极显著<清水处理,其对小麦的降秆作用主要是缩短了第3~5节的节间长度,而对第1~2节的节间长度影响不大;抽穗期和开花期均较对照推迟2 d。在较强的杀雄效果下,豆草除TM对小麦生长发育的影响与其他化学杀雄剂相同,且费用便宜,因此,大豆除草剂豆草除TM有可能作为一种新的小麦化学杂交剂,应用于小麦杂种优势利用研究。

Screen of Different Cotton Varieties under Dry Land Conditions in Namibia

Cotton has been identified as a crop with promising potential in Namibia.As such,cotton variety evaluation trials have been conducted for yield,fiber qualities,resistance to diseases and pests。

小麦抗旱新种质衡562性状表现及分析

连续9年通过对普通小麦基因型石4185(T.aestivum)与硬粒小麦基因型4184(T.durum)种间杂交后代回交、顶交及辐射处理,选育出节水、高产小麦新种质衡562。近红外技术测定,抗旱指数为1.2。2008～2009年河北省农林科学院旱作农业研究所作水、旱处理,水地产量442.39 kg/667 m2,比对照石4185(400.26 kg/667 m2)增产10.53%;旱地产量366.39kg/667 m2,比对照石4185(334.53 kg/667 m2)增产9.52%。2009～2010年在河北省区域试验节水组预备试验中,平均产量394.97 kg/667 m2,比对照增产9.06%,名列24个参试品种第1名。衡562的育成,为小麦节水、抗旱育种提供了具有应用价值的新种质资源。

Comparative Effects of Organic Cocoa Shell-Based and Inorganic NPK Fertilization on the Growth and Yield of Four Cassava Varieties

Looking of finding an alternative to the use of chemical fertilizers to increase yields of cassava (Manihot esculenta), trials were carried out in the Lamto zone in central Côte d’Ivoire. Thus, the effects of compost and ash from cocoa shell and NPK were tested on the agronomic parameters of cassava. The trial was conducted for two years with four varieties of cassava: Yacé, Alleda agba, Six mois and Bonoua, grown on elementary plots treated with one of these fertilizers. The experimental design was complete randomized blocks with three replicates. Analysis of the results showed that the Six mois variety gave the longest stems (131, 67 cm) with the cocoa shell compost. The Bonoua variety, on the other hand, gave the largest diameter of the stem base (21.56 mm), a higher number of leaves (77.30) and a large wingspan (136.89 cm) with cocoa shell compost. The leaves developed by the plants of this variety were wider (19.30 cm) and longer (17.96 cm) with cocoa shell compost. Also, this Bonoua variety treated with shell compost yielded a high number of tuberized roots (5.11), high average weight per plant (5.83 kg/plant) and higher yield (58.29 t/ha). This compost of cocoa shell has also allowed a better conservation of the cultivated soils quality.

Endophytic mediation of reactive oxygen species and antioxidant activity in plants:a review

Reactive oxygen species are in all types of organisms from microbes to higher plants and animals.They are by-products of normal metabolism,such as photosynthesis and respiration,and are responsive to abiotic and biotic stress.Accumulating evidence suggests reactive oxygen species play a vital role in programmed cell death,stress responses,plant defense against pathogens and systemic stress signaling in conjunction with antioxidant production.Here,we propose that reactive oxygen species and antioxidants,as both universal and evolutionarily conserved,are likely to play important role(s)in symbiotic interactions.To support this hypothesis we review the root and foliar fungal endophyte literature specific to fungal-plant symbiotum production of reactive oxygen species and antioxidants in response to stress.These asymptomatic fungi can produce antioxidants in response to both biotic and abiotic stress when grown in culture as well as in planta.In addition,there is a growing but nascent literature reporting a significant impact of endophyte colonization on the antioxidant activity of colonized(E+)hosts when compared to uncolonized(E-)hosts,especially when exposed to stress.Here we summarize general patterns emerging from the growing literature specific to antioxidant activity of endophytes in colonized hosts and bring up possible future research questions and approaches.The consequences of changes in reactive oxygen species production and increased antioxidant activity in the symbiotum appear to be beneficial in many instances;but costs are also indicated.Unexplored questions are:1)to what extent do antioxidants originating from the fungal endophyte mediate host metabolism,and thereby control host responses to endophyte colonization;(2)what role do fungal,plant,or symbiotum produced reactive oxygen species and antioxidants have in determining symbiotic outcome between extremes of pathogenicity and mutualism;and(3)what role if any,do the production of reactive oxygen species and their antioxidant counterparts play in the symbiotum’s ability to respond to changing selection pressures?If as the literature suggests,such endophyte imposed mediation can be utilized to foster increases in plant production in resource limited habitats then the utilization of fungal endophytes may prove useful in agronomic and conservation settings.

Non-systemic fungal endophytes in Festuca rubra plants infected by Epichloë festucae in subarctic habitats

Epichloëfestucae is an endophytic fungus that infects systemically the aerial tissues of the host grass Festuca rubra.This fungus is transmitted vertically from the mother plant to seeds.Hypothetically,the presence of E.festucae could affect the infection of a plant by other fungal species.This could occur if E.festucae metabolites produced in planta interfere negatively with other fungal infections;or alternatively,if the modulation of plant defenses by the endophyte favour further fungal infections.We have analyzed the presence of culturable non-systemic endophytes in plants of F.rubra infected(E+)and not infected(E−)by E.festucae in two subarctic habitats,meadows and riverbanks in Northern Finland.The observed non-systemic endophyte infection frequencies were similar among E+and E−plants from riverbanks,and E+plants from meadows.In contrast to these,the infection frequency was significantly lower in E−plants from meadows.This result suggests that the presence of E.festucae is not a main factor determining the presence of non-systemic endophytes in plants.Instead,plant genetic characteristics related to compatibility with E.festucae and other endophytes in the more stable meadow populations might play a role in these fungus–fungus–plant interactions.As a result of the survey,18 different taxa of non-systemic endophytes were identified in plants of F.rubra.All were ascomycetes except for one basidiomycete.Three endophytic taxa could not be ascribed to a genus,but sequence data indicated that they were conspecific with other unidentified endophytes that have been isolated in cold biomes at different locations.

咪唑乙烟酸对小麦品种衡观35挑旗期杀雄效果及农艺性状的影响

在小麦挑旗期（Feekes 9.0）分别以10%咪唑乙烟酸125.6mL/hm^2、185.9mL/hm^2和251.3mL/hm^2的用量对小麦进行喷雾,结果表明：（1）同对照相比,咪唑乙烟酸对小麦株高、穗长、小穗数及穗粒数影响严重,除125.6mL/hm^2的用量对小穗数影响差异不显著外,其他性状均达到极显著水平;（2）对植株各茎节进行解剖,降秆主要发生在第3-5节,各处理第1-2节间与对照差异不显著,其余各节间均达到极显著水平;（3）抽穗期、开花期较对照晚2d;（4）发现咪唑乙烟酸新功能,在小麦挑旗期（Feekes 9.0）喷雾后能诱导95.6%-99.1%的雄性不育,有可能作为一种新的小麦雄性不育诱导剂,应用于小麦杂种优势的研究。

Neotyphodium fungal endophyte in tall fescue (Schedonorus phoenix): a comparison of three Northern European wild populations and the cultivar Kentucky-31

Pooideae grasses may be colonized by systemic fungal endophytes.The fitness of endophyte depends entirely on resources and seed transmission from the host plant,while colonized plants may gain increased survival,growth,and reproduction relative to their uncolonized conspecifics.Most research of endophyte-grass interactions have been carried out on few cultivars of tall fescue(Schedonorus phoenix)and their symbiont Neotyphodium coenophialum.Lack of studies using wild populations of tall fescue across the species natural distribution range,however,limits the understanding of the ecological and evolutionary role of the symbiosis in nature.We performed a common garden experiment in Southern Finland with three wild,tall fescue populations from northern Europe and the forage cultivar Kentucky-31(KY-31).For each population,we used naturally endophyte-colonized,naturally endophytecolonized but endophyte removed(decolonized),and naturally uncolonized plants to separate effects due to the host genotype from the endophyte.We evaluated growth variables and survival in four environmental treatments of varying water and nutrients.Supply of water and nutrients increased plant biomass and reproductive effort in all populations.This effect was higher for KY-31 plants which produced on average 55%more seeds than wild plants,indicating better adaptation to high resource environments.However,the higher incidence of Claviceps sp.and the low winter survival indicated KY-31 tall fescue is mal-adapted to Northern European conditions.Naturally colonized plants had greater plant biomass(≈12%),reproductive effort(≈22%)and seed mass(≈29%)than naturally uncolonized and decolonized plants.Nonetheless,endophyte colonization did not affect plant survival,and the effects of endophyte colonization on tiller number,panicle/tiller ratio and Claviceps sp.incidence depended on the population origin.In the wild populations,endophyte removal only reduced the number of tillers(≈29%lower),while the difference between naturally colonized and naturally uncolonized plants was not significant.Our results show that endophyte symbiont increases tall fescue performance in general,but the differences between wild populations and cultivars indicate adaptation to local habitats and agronomic management,respectively.The comparison of naturally endophyte-colonized and decolonized plants suggests certain plant genotype-endophyte combinations found within populations result from local selection pressures.

Fungal endophyte mediated occurrence of seminiferous and pseudoviviparous panicles in Festuca rubra

Fungal endophytes are suggested to manipulate host grass reproduction.Using different grass-endophyte combinations in a four year common garden experiment,we show that endophyte can retain control over the reproductive functions of the host.Plants were collected as seeds from two different environments,meadows and riverbanks.Natural endophyte infection(E+)increased reproductive effort of plants;13 and 15%higher proportion of E+plants produced panicles compared to naturally uninfected(E-)and manipulatively endophyte-infected(ME+)plants,respectively.Meadoworigin E+plants produced also higher number of panicles compared to E-in the last two years,and both meadow-and riverbank-origin ME+plants produced higher number of panicles compared to ME-plants in most of the years.Pseudovivipary was recorded in 5%of the plants each year.Pollen limitation appears not to induce pseudovivipary.Both E+and ME+plants produced higher number of seminiferous panicles compared to E-and ME-plants.The higher proportion of pseudoviviparism in ME+plants compared to E+,Eand ME-plants from meadows suggests specific genotypegenotype cross-talk between endophyte and grass.Pseudovivipary was affected by year and primarily explained by plant reproductive effort since most vigorous plants produced more pseudoviviparous panicles.We propose that endophytes can promote host grass reproduction in a habitatspecific manner and depending on genetic compatibility between partners.However,reproductive behavior depended on maternal habitat and the annual environmental conditions highlighting the importance of long-term experiments to estimate the effects of endophytes on host plant ecology.