高产和优质是棉花育种的主要目标.产量与纤维品质多呈负相关关系,产量和纤维品质难以同步提高.采取相应育种对策和方法,以打破目标性状基因与不利性状基因连锁,应是棉花产量、纤维品质育种的关键.在此,对棉花产量、纤维品质育种的主要方法进行简要剖析,以供参考.

介绍了优质鲜食及加工型紫薯新品种徐紫薯8号的遗传背景、生物学性状、营养品质、适种区域和加工价值等品种特性.同时,初步探究了徐紫薯8号的高效优质栽培技术,以促进鲜食及加工利用甘薯品种的推广与利用.

为了解甘薯钾离子转运蛋白HKT基因家族的功能,分析低钾胁迫下的基因表达模式,利用甘薯(泰中6号)基因组信息,分离得到4个HKT基因家族成员,分析了基因结构、亚细胞定位、跨膜结构、系统进化树等;并研究了低钾胁迫下,徐薯22和宁紫1号2个不同耐低钾型品种的表达模式.结果显示:1)甘薯4个HKT蛋白都定位到了质膜上,具有6～7个不等的跨膜区;2)对拟南芥、水稻、玉米和甘薯等作物的HKT进化分析表明,HKTs可聚为3个进化簇,但甘薯IbHKT2和IbHKT4独自组成1个进化簇;3)IbHKT基因家族成员分布在甘薯的第3号染色体上,IbHKT1和IbHKT3、IbHKT2和IbHKT4是由于染色体片段复制导致的同源基因;4)实时定量荧光PCR分析表明,IbHKT基因受低钾胁迫诱导表达,但诱导程度在徐薯22和宁紫1号间存在差异.

The present study investigated the roles of exogenous hormones in mitigating the loss caused by potassium (K+) deficiency stress in terms of plant growth and physiology in sweet potato (Ipomoea batatas L. [Lam.]). Two cultivars, Xushu 32 (tolerant to K+ deficiency) and Ningzishu 1 (sensitive to K+ deficiency) were used for the study. Exogenous hormones (indole-3-acetic acid, IAA; gibberellin 3, GA(3); abscisic acid, ABA) were applied foliarly on the 14(th) day of K+ deficiency stress (-K). After 5 days of application, the exogenous hormones significantly increased the chlorophyll content (Chl) and net photosynthetic rate (P-n), as well as the activities of antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT) in leaves, while reduced the lipid peroxidation levels (hydrogen peroxide, H2O2 and malondialdehyde, MDA). Application of hormones also significantly increased the root activity and alleviated the root tip cell damage. All these changes led to the enhancement of the plant dry weight, K+ content and K+ accumulation under - K condition, indicating that exogenous hormones can be used as potential tools to improve the K+ deficiency tolerance of sweet potato. However, exogenous IAA has a better effect on Xushu 32 than GA(3) and ABA, while ABA is the best for Ningzishu 1.

Sweetpotato (Ipomoea batatas (L.) Lam.) is an important industrial and food crop. Both chilling and heat stress inhibits sweetpotato growth and development and then affects yield. However, the physiological and molecular mechanisms of sweetpotato response to chilling and heat stress is unclear. In this study, we investigated the effect of extreme temperature on sweetpotato physiological response, with a focus on oxidative stress and the potential microRNA (miRNA)-mediated molecular mechanism. Our results showed that both chilling and heat stress resulted in accumulation of reactive oxygen species (ROS), including H2O2 and O2 -, and caused oxidative stress in sweetpotato. This further affected the activities of oxidative stress-related enzymes and products, including SOD, POD, and MDA. Both chilling and heat stress inhibited POD activities but induced the enzyme activities of SOD and MDA. This suggests that sweetpotato cells initiated its own defense mechanism to handle extreme temperature-caused oxidative damage. Oxidative damage and repair are one mechanism that sweetpotato plants respond to extreme temperatures. Another potential mechanism is miRNA-mediated gene response. Chilling and heat stress altered the expression of stress-responsive miRNAs in sweetpotato seedlings. These miRNAs regulate sweetpotato response to extreme stress through targeting individual protein-coding genes.

The present study investigated the roles of exogenous hormones in mitigating the loss caused by potassium (K+) deficiency stress in terms of plant growth and physiology in sweet potato (Ipomoea batatas L. [Lam.]). Two cultivars, Xushu 32 (tolerant to K+ deficiency) and Ningzishu 1 (sensitive to K+ deficiency) were used for the study. Exogenous hormones (indole-3-acetic acid, IAA; gibberellin 3, GA(3); abscisic acid, ABA) were applied foliarly on the 14(th) day of K+ deficiency stress (-K). After 5 days of application, the exogenous hormones significantly increased the chlorophyll content (Chl) and net photosynthetic rate (P-n), as well as the activities of antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT) in leaves, while reduced the lipid peroxidation levels (hydrogen peroxide, H2O2 and malondialdehyde, MDA). Application of hormones also significantly increased the root activity and alleviated the root tip cell damage. All these changes led to the enhancement of the plant dry weight, K+ content and K+ accumulation under - K condition, indicating that exogenous hormones can be used as potential tools to improve the K+ deficiency tolerance of sweet potato. However, exogenous IAA has a better effect on Xushu 32 than GA(3) and ABA, while ABA is the best for Ningzishu 1.

棉花枯萎病和黄萎病是棉花生产上危害严重且药剂难于防治的两种土传性维管束病害,选育和应用抗病品种是防治两种病害的有效途径.目前,棉花抗病育种尤其是抗黄萎病育种进展缓慢,至今没有真正的抗黄萎病品种育成,棉花对枯萎病和黄萎病尤其是黄萎病的抗性遗传机理尚未完全弄清是其主要原因之一.在此,对棉花枯萎病和黄萎病的抗性遗传进行简要剖析,以供参考.

为探讨氮肥用量和栽插密度与鲜食型甘薯产量、品质及淀粉糊化特性的关系,以徐薯32和徐紫薯5号为试验材料,设置3个施氮量(N)水平和5个密度(D)水平,于2017,2018年进行了田间试验.结果表明:两品种的薯块产量随施氮量的增加呈下降趋势,随密度的增加呈先下降后上升趋势,总体上在N0(0 kg/hm2)和D1(43785株/hm2)水平下薯块产量最高.施氮使2个甘薯品种的干物质率降低,而显著增加了蛋白质含量;随栽插密度的增加,干物质率、淀粉和蛋白质含量总体上呈先升高后降低的趋势,还原糖含量总体呈下降趋势,而可溶性糖含量呈波动变化,均在D3水平下最低.施氮总体上使两品种块根的淀粉最高黏度、最低黏度和崩解值明显降低,消减值均明显升高,造成蒸煮食味品质的下降;两品种的最高黏度、最低黏度、崩解值和最终黏度值均随着密度的增加呈波动变化,徐薯32在D3水平下最大,而徐紫薯5号在D2水平下最高;施氮量和栽插密度对甘薯淀粉RVA谱的影响存在品种间和特性间的差异.综合本试验结果,在土壤肥力较高的地块大量施氮使甘薯产量下降,并降低了薯块营养品质和食味品质;在43785株/hm2的密度水平下薯块产量最高,但适当增加密度有利于营养品质和蒸煮食味品质的提高.

棉花是常异花授粉作物,高产和优质是棉花育种的主要目标.棉花纤维品质与产量多呈负相关关系,产量和纤维品质难以同步提高.目标性状基因与不利性状基因连锁是产量与纤维品质间呈负相关关系的主要原因.棉花纤维品质育种只有采取相应对策和方法,才能取得较好的育种效果.在此,对棉花纤维品质育种的主要方法进行简要剖析,以供参考.

介绍了河北盐碱旱地棉花机采种植模式五统一栽培新技术的主要栽培要点、推广示范效果、新技术适用区域和应用注意事项.

棉花属常异花授粉作物,而且种子生产、加工环节多,极易造成棉花品种的混杂退化.棉花品种的混杂退化会造成产量下降和纤维品质变劣,并逐渐丧失其生产利用价值.本文对棉花品种混杂退化的主要原因及提纯复壮的主要途径进行简要剖析,以供参考.

棉花抗病育种主要是选育兼抗枯、黄萎病,并具有高产、优质特点的新品种.在此,对棉花抗病育种常用途径和方法进行简要剖析,以供参考.

棉花属常异花授粉作物,而且种子生产、加工环节多,比自花授粉作物更易造成品种的混杂退化.混杂退化直接导致棉花品种的种性下降.在此,对棉花品种种性下降的主要原因及保持和提高棉花品种种性的主要对策进行简要剖析,以供参考.

A long-term located fertilization experiment in fluvo-aquic soil region was carried out to study the effects of differ-ent chemical fertilizer application modes on the biomass, nutrient uptake and nutrient distribution of sweet potato. The results showed that the treatments NP and NPK all could significantly increase the vine length, branch number, above-ground biomass and root tuber biomass of sweet potato,and the treatment NPK obtained the best effects. The quantity of nitrogen,phosphorus and potassium absorbed by the above-ground part and root tuber of sweet potato in different treatments all revealed the following order:NPK>NP>N>CK. The soil potassium deficiency appeared in the treatment NP, while the soil nitrogen surplus in the treatment N was the highest, being 86.64 kg/hm2. So, the combined application of nitrogen, phosphorus and potassium fertilizer in the pro-duction of sweet potato should be paid attention to.

杂交育种是棉花育种的主导方法.在杂交育种过程中,杂交方式是影响杂交育种成效的重要因素之一.在此,对棉花杂交育种的主要杂交方式进行简要剖析,以供参考.

以潮土长期施肥试验为研究平台,研究有机碳含量及小麦产量对8种不同施肥方式的响应,并分析产量变异系数及可持续性指数与有机碳含量的关系,为指导潮土区的合理施肥提供科学依据.结果发现,有机无机配施处理土壤有机碳平均含量增幅最大,小麦产量最高,产量稳定性最高,最为有利于保持潮土养分均衡,促进农田生产力稳定.结果表明,土壤有机碳含量与小麦产量极显著正相关(P<0.01),小麦产量变异系数(CV)、可持续性指数(SYI)均与土壤有机碳平均含量显著相关(P<0.05),施用有机肥提高小麦产量及其稳定性的主要原因可能是提高了土壤有机碳含量.

杂交育种是棉花育种的主导方法.在杂交育种过程中,创造所需要的新的遗传变异是基础,采取适宜的方法进行遗传变异的选择和固定是关键.杂交育种后代遗传变异选择处理的方法主要有系谱法、混合法、衍生系统法和单籽传法等.在此,对棉花杂交育种后代选择处理的主要方法进行简要剖析,以供参考.

遗传型方差σg2、环境方差σe2、遗传率h2、遗传变异系数(GCV)等是棉花数量性状的主要遗传参数.对其进行估算和分析,能够对棉花数量性状的主要遗传特点进行较好的诠释,而且对棉花育种实践也具有重要的指导意义.在此,对主要遗传参数在棉花育种实践上的意义进行简要剖析,以供参考.

[目的]探讨潮土有效磷的农学阈值,为潮土区科学施用磷肥提供理论依据.[方法]以35年长期定位试验为研究平台,分析长期不同施肥下土壤全磷、有效磷及PAC值对8种施肥方式(CK、N、NP、NPK、M、MN、MNP、MNPK)的响应规律.[结果]经过35年不同施肥,不施磷肥的处理(CK、N)土壤全磷、有效磷含量均有所下降;化学磷肥处理(NP、NPK)土壤全磷含量出现升高;单施有机磷肥处理及有机无机磷肥配施(M、MN、MNP、MNPK)土壤全磷和有效磷均有显著提高,年增加量分别为0.007、0.005、0.013、0.015 g/kg和0.93、0.84、1.39、1.24 mg/kg,其中仅MNP处理土壤PAC值提高幅度达到显著水平.[结论]通过分析小麦相对产量和土壤有效磷的变化趋势,土壤有效磷农学阈值为13.41 mg/kg.

Sweetpotato (Ipomoea batatas L.) is a globally important economic food crop. It belongs to Convolvulaceae family and origins in the tropics; however, sweetpotato is sensitive to cold stress during storage. In this study, we performed transcriptome sequencing to investigate the sweetpotato response to chilling stress during storage. A total of 110,110 unigenes were generated via high-throughput sequencing. Differentially expressed genes (DEGs) analysis showed that 18,681 genes were up-regulated and 21,983 genes were down-regulated in low temperature condition. Many DEGs were related to the cell membrane system, antioxidant enzymes, carbohydrate metabolism, and hormone metabolism, which are potentially associated with sweetpotato resistance to low temperature. The existence of DEGs suggests a molecular basis for the biochemical and physiological consequences of sweetpotato in low temperature storage conditions. Our analysis will provide a new target for enhancement of sweetpotato cold stress tolerance in postharvest storage through genetic manipulation.