Some consequences of pollen storage in the raspberry (Rubus idaeus L.)

Summary Raspberry pollen was stored at 5°C and –13°C for six months and then tested for its ability to induce pyrene set and the production of viable seedlings, and for its effect upon the segregation of a major gene s. Only pollen stored at –13°C gave a pyrene set and germination percentage adequate to produce sufficient seedlings for a breeding programme. It is suggested that tests of pollen viability in the raspberry should include studies of pollen germination, and the effect of this pollen on pyrene set and seed germination. Possible causes of the loss of viability in the pollen stored at 5°C are discussed.     

Inheritance of resistance to powdery mildew Sphaerotheca macularis (Fr.)Jaczewski in the red raspberry,Rubus idaeus L.

Summary The varieties Lloyd George and Burnetholm (and probably Malling Promise) are heterozygous for three genes governing resistance to mildew (S. macularis (FR.) Jaczewski, syn. S. humuli (DC.) BUrr.), Sp ₁ and Sp ₂ being dominant complementaries and sp ₃ recessive. Resistance whether of Sp ₁, Sp ₂ or sp ₃ sp ₃ origin is epistatic to susceptibility. Sp ₃ is linked with the fruit colour gene T with a crossover value of ca. 25%, the gene order in this linkage group being B-Sx ₃-T-Sp₃.Evidence suggesting linkage between H (hairy canes) and resistance is presented.     

Effect of non-conventional atmospheres and bio-based packaging on the quality and safety of Listeria monocytogenes-inoculated fresh-cut celery (Apium graveolens L.) during storage

The increased consumption of fresh-cut celery has led to the need to explore packaging alternatives for fresh-cut celery that can meet consumer, market, and industry needs. In this study, the effect of bio-based packaging and non-conventional atmospheres on the quality and safety of chlorine-sanitized celery sticks stored at 7 °C was investigated. Two materials differing in permeability [a bio-based polyester (polylactic acid (PLA)) and a petroleum-based polyolefin (polypropylene/low density polyethylene (PP/PE)] and four initial gas compositions [air (A-PLA or A-PP/PE), 95 kPa O₂ + 5 kPa N₂ (O₂-PLA), 99 kPa N₂ + 1 kPa O₂ (N₂-PLA), and 6 kPa O₂ + 12 kPa CO₂ + 82 kPa N₂ (CO₂-PLA)] were evaluated. Changes in headspace composition, weight loss, surface and cut end color, texture, ethanol content, appearance, and growth of Listeria monocytogenes on inoculated celery sticks were assessed during 21 d of storage. Active MAP (CO₂-PLA) out-performed passive MAP (A-PLA) in maintaining celery stick quality but not safety. Conventional active MAP (CO₂-PLA) out-performed non-conventional active MAPs (O₂-PLA and N₂-PLA) in maintaining celery stick quality throughout storage, but O₂-PLA suppressed L. monocytogenes growth while CO₂-PLA promoted growth during the first 10 d of storage. PLA and PP/PE materials affected celery stick quality but not Listeria growth. This study shows that the initial gas composition and packaging material both impact the quality and safety of celery sticks. Overall, the combination PLA and 95 kPa O₂ proved most beneficial in maximizing both the safety and quality of celery sticks during one week of storage at 7 °C.     

Influence of aqueous 1-methylcyclopropene concentration, immersion duration, and solution longevity on the postharvest ripening of breaker-turning tomato (Solanum lycopersicum L.) fruit

The influence of aqueous 1-methylcyclopropene (1-MCP) concentration, immersion duration, and solution longevity on the ripening of early ripening-stage tomato (Solanum lycopersicum L.) has been investigated. Tomato fruit at the breaker-turning stage were fully immersed in aqueous 1-MCP at 50, 200, 400 and 600 μg L⁻¹ for 1 min, quickly dried, and then stored at 20 °C. Ethylene production, respiration, surface color development, and rate of accumulation of lycopene and polygalacturonase (PG) activity were suppressed and/or delayed in fruit exposed to aqueous 1-MCP. Suppression of ripening was concentration dependent, with maximum inhibition in response to 1 min immersion occurring at concentrations of 400 and 600 μg L⁻¹. Climacteric ethylene peaks were delayed approximately 6, 7, and 9 d and respiration was strongly suppressed in fruit treated with aqueous 1-MCP at 200, 400, and 600 μg L⁻¹, respectively, compared with control fruit. Fruit firmness, lycopene content, PG activity, and surface hue of fruit treated at the three higher levels remained strongly suppressed compared with control. Skin hue values and pericarp lycopene content in response to treatment at the subthreshold 50 μg L⁻¹ provided evidence for differential ripening suppression in external versus internal tissues. Maximum delay of softening and surface color development in response to 50 μg L⁻¹ aqueous 1-MCP occurred following immersion periods of between 6 and 12 min. Factors affecting fruit penetration by aqueous 1-MCP and mechanisms contributing to recovery from 1-MCP-induced ripening inhibition are discussed.     

Effects of ultrasound and high pressure argon on physico-chemical properties of white mushrooms (Agaricus bisporus) during postharvest storage

Effects of high pressure argon (H), ultrasound (U) and their combination treatments (UH) on physico-chemical characteristics of white mushrooms were studied during 9 d of postharvest storage at 4 °C. H treated samples exhibited the smallest weight loss and respiration rate compared to all other samples. Mass losses after 9 d of storage were 3.01%, 5.09%, 5.39% and 9.59% for H, UH, U and untreated mushrooms, respectively. Furthermore, U treated samples showed lower polyphenol oxidase activity (PPO, E.C. 1.14.18.1) during storage while UH treated samples showed a slight increase in antioxidant capacity during storage and also experienced reduced mass loss and respiration rate. In addition, treated samples were effective in retaining mushrooms colour changes compared to control. Physico-chemical properties of differently treated mushrooms (UH, H and U) stored at 4 °C were significantly different (p < 0.05) from control.     

Effect of combined application of heat treatments and plastic packaging on keeping quality of ‘Oroblanco’ fruit (Citrus grandis L.×C. paradisi Macf.)

Combinations of various heat treatments with individual fruit sealing, packaging in polyethylene liners or waxing were tested as means to control pathological and physiological spoilage of ‘Oroblanco’ fruit (Citrus grandis L.×C. paradisi Macf.). The following heat treatments were used: curing at 36°C for 72 h, hot water dip at 52°C for 2 min or ‘hot drench brushing’ at 52, 56 or 60°C for 10 s. The standard packinghouse treatment included waxing with addition of thiabendazole (TBZ) and 2,4- isopropyl ester. The fruit was stored for 2 weeks at 1°C (simulated low-temperature quarantine treatment), followed by 12–13 weeks at 11°C (simulated sea transportation to Japan) and 1 additional week at 20°C (simulated retail shelf-life period). The lowest weight loss and the highest firmness were observed with individually sealed fruit. Polyethylene liners were usually more efficient for weight loss control than waxing. However, the liner packaging enhanced the risk of postharvest disease development, if not accompanied by appropriate decay-controlling measures. Applying TBZ, hot water dip or curing controlled the development of postharvest pathogens, especially that of Penicillium molds. In another trial, both hot drench brushing at 56 or 60°C and hot water dip reduced decay incidence. Hot drench brushing at 60°C and hot water dip slowed fruit softening and reduced buttons abscission. In addition, the hot drench brushing at 60°C significantly delayed the loss of ‘Oroblanco’ green rind color, especially at the stylar and stem ends of the fruit. The hot dip at 52°C inhibited yellowing only when combined with individual seal-packaging.     

A comparison of microtubers and field-grown tubers of potato (Solanum tuberosum L.) for hexoses, sucrose and their ratios following postharvest cold storage

Cold-induced sweetening (CIS) is a significant postharvest problem in processing potato (Solanum tuberosum L.) tubers. A rise in hexose sugar levels during cold storage results in a brown, bitter tasting and unmarketable product. We tested if potato microtubers (MicroT) can undergo CIS and if this corresponds to the CIS response in field-grown tubers (FieldT) with the hope of fast-tracking breeding programmes using a MicroT system. Using MicroT from potato genotypes representing a range of CIS response levels we have demonstrated that MicroT undergo CIS more rapidly than FieldT. Correlations of glucose:sucrose and hexose:sucrose ratios were highly significant between the two tuber types after cold treatment and these ratios are known to be good predictors of invertase activity, a key regulator of CIS. Correlations of individual sugars were non-significant before and after postharvest cold treatment.     

2010年中国草地螟轻发年份的新特点与成因探讨

为揭示草地螟在中国北方农牧区发生危害的年度间变化规律,探明轻发年份的成因和警示意义,通过10个主发省份多个监测点规范连续、广泛系统的测报调查及历史数据比对,得出以下结论：2010年草地螟发生面积是第三个暴发周期以来最小的一年,在这一轻发年份中,出现了山西北部一代成虫集中迁入、二代幼虫局部成灾,新疆阿勒泰地区首见二代幼虫和越冬茧等新的特点。分析讨论了2010年北方大部农牧区草地螟轻发的主要原因有：2009年境内越冬虫源量少,2010年春季无大规模境外虫源迁入,且大部地区气候和生态条件不适于草地螟的发生。重点指出了境外虫源和小生境条件对山西等地草地螟异常发生的影响,新疆阿勒泰地区发现二代幼虫和越冬茧的意义,虫源保留地对草地螟种群延续的作用以及在轻发年份加强监测和研究工作的理由。     

Development of a new initial breeding material in sunflower (Helianthus annuus L.) using direct organogenesis and somatic embryogenesis

Summary Immature zygotic embryos from three inbred lines of sunflower (Helianthus annuus L.) were used as donor material for the induction of direct organogenesis and somatic embryogenesis. The scope of the spontaneously appearing somaclonal variation has been studied among the regenerants produced according to the method of Freyssinet & Freyssinet (1988), and was compared to the results obtained after gamma ray mutagenesis (7 and 10 Gy). Freshly excised immature zygotic embryos were used for irradiation treatment. Genetic changes occurring spontaneously during the regeneration procedure were observed for date of flowering, vegetation period, plant height, head diameter, 1000 seed weight, kernel oil content, and fatty acid composition. The mutagenic treatment had a marked stimulatory effect on the frequency of the regenerants produced and the degree of the observed changes. The 7 Gy treatment was most efficient for the majority of the characters studied. The type of changes was correlated with the genotype. The degree and type of somaclonal variation, with or without mutagenic treatment, should be sufficient for an application in the production of new breeding material.     

单粒精播对花生根系生长、根冠比和产量的影响

以大粒型花生品种花育22为试验材料,设每公顷19.5万穴(S1)和22.5万穴(S2) 2个单粒播处理,双粒穴播每公顷15万穴处理为对照进行大田试验,对比单粒精播与双粒穴播对花生耕层根系生长动态、根冠比和产量的影响差异。与对照相比,单粒精播S1处理在开花后50~70 d的根系形态指标和干物质积累动态明显改善,耕层根系长度、体积和吸收面积在0.05水平上显著增加,根系干物质积累量(DMA)和积累速率(DMAR)也明显提高;S1和S2处理开花后40~70 d根冠比明显提高,并保证冠层和荚果较高的DMA和DMAR,通过提高单株生产力,实现群体增产,其中S1处理为佳,可在节种35%的前提下,增产7.98%~8.38%,增产效果显著。本研究说明单粒精播可保证花生根系相对较强的生长优势,协调根冠比,壮个体,强群体,充分发挥单株生产潜力,实现花生高产。     

Effects of photoperiod and temperature on flowering in mungbean (Vigna radiata (L.) Wilczek)

Summary Forty strains of mungbeans, including all of the entries in the 1st and 2nd International Mungbean Nurseries (IMN), were grown in plant growth chambers in photoperiods of 12, 13, 14, 15, and 16 hours and mean temperatures of 18, 23, and 28°C. Results show that (1) mungbean strains differ in their flowering response to photoperiod and to mean temperature; (2) increasing the photoperiod of reducing the mean temperature delayed flowering, the amount of delay varied with the strain: (3) variations in mean temperature may alter the effect of the photoperiod on flowering in particular strains. Twenty-five strains which flowered in all photoperiod-temperature treatments could be divided into four groups, each group being successively later in flowering. The remaining 15 strains could be divided into four groups, according to their failure to flower within 105 days in specific photoperiod-temperature treatments. Flowering response in the growth chamber is useful in explaining flowering response in the 2nd IMN at three locations varying from 14°N to 49°N latitude.Contribution No 7516 from the Missouri Agricultural Experiment Station.     

Some Effects of Soil Salinity on Growth, Development and Yield of Rapeseed (Brassica napus L.)

The effects of increasing soil-salt levels on emergence, shoot and root growth and yield composition of rapeseed were investigated. A range of electrical conductivity (EC) values in the soil solution from 2.3 dS m^-1 to 10.3 dS m^-1 was obtained by adding NaCl to the substrate. The emergence was significantly (P < 0.05) decreased at EC values higher than 6 dS m^-1 Above this value, a delay in the appearance of leaves and of the first visible internode was observed. The further increase of salinity level extended the period for siliqua formation and grain filling, and plant height, pod number and grain number per plant were lowered. However, the cultivar used showed the ability of counterbalancing for this lower grain number by increasing the seed weight, thus there were no variations on seed yield. The seed oil and protein content were also not affected by the changes in salinity. Root growth was adversely affected when salinity levels exceeded 6 dS m^-1. Beyond this value, short tuber-like roots became remarkably frequent. This may be an adaptation mechanism of this species to saline stress; a similar reaction in rapeseed is known in adaptation to drought stress.     

源库改变对小麦籽粒蛋白质,淀粉含量及产量的影响

利用蛋白质含量及产量各不相同3个春小麦品种．研究了源库改变对淀粉、蛋白质沉术；及单侏产量的影响．结果表明：源库改变明显地影响着籽粒蛋白质的含量，而对淀粉、可溶性糖含量影响不大；品种间蛋白质含量对源库变化的反应不同；千粒重的增减也因品种而异；淀粉的沉积主要受库的限制，而源库都影响着蛋白含量；旗叶在产量和蛋白形成中起着同样重要作用。     

播期对胡麻产量、品质、农艺性状的影响研究

为了进一步明确播期对胡麻产量、品质和农艺性状的影响,本研究选用5个胡麻品种,设置4个播期,调查了产量、品质和农艺性状相关的15个性状。结果表明：（1）随着播期的推迟,5个胡麻品种的单产显著减少,籽粒的营养物质主要表现为减少趋势,其中棕榈酸含量能够保持稳定或略有增加;（2）‘坝选十六’和‘选三’的单产在4个播期均高于其他品种,其中‘坝选十六’的单产最高,而且含有丰富的亚麻酸、亚油酸、蛋白质、木酚素等营养物质,含油率较高,为供试品种中的最佳品种。本研究进一步量化了播期对胡麻产量、品质和农艺性状的影响,早播有利于获得高产、增强品质,并且筛选出‘坝选十六’为最佳品种,为胡麻生产的良种良法配套提供理论依据。     

Effects of Deficit Irrigation and Salinity Stress on Common Bean (Phaseolus Vulgaris L.) and Mungbean (Vigna Radiata (L.) Wilczek) Grown in a Controlled Environment

As water for irrigation purposes becomes increasingly scarce because of climate change and population growth, there is growing interest in regulated deficit irrigation (RDI) as a way to improve efficiency of water usage and farm productivity in arid and semi‐arid areas. Salinity is also becoming an important problem in these same regions. Experiments were performed to investigate the effects of RDI and salt stress on two legumes crops, common bean (Phaseolus vulgaris L.) and mungbean (Vigna radiata (L.) Wilczek); previous work showed contrasting responses to RDI by these two crops under field conditions. The seed and biomass yields of both crops were reduced as a result of increasing water deficit stress; however, mungbean was able to maintain the same proportion of its biomass in reproductive structures and maintain its harvest index under stress, whereas common bean’s decreased. In addition, photosynthesis in mungbean was higher than in common bean and higher at the same levels of transpiration. Finally, salinity stress did not affect the water potential, harvest index or the specific leaf weight of either crop. There were no interactions between salinity and crops or RDI levels, which suggest that the two crops do not differ in their response to salinity stress, and that RDI levels do not modify this response.     

Effects of Thiourea, Thiamine and Ascorbic Acid on Growth and Yield of Maize (Zea mays L.)

Three chemicals, viz., thiourea, thiamine and ascorbic acid capable of potentiating-SH turnover, were tested with the objective to improve growth and productivity of maize. Thiourea was tested as seed-soaking and foliar-applied treatments as also in combination. Thiamine and ascorbic acid were tested as foliar sprays alone. Foliar treatments were applied at vegetative stage (30 and 45 days after sowing).
The results of the field experiment showed that seed soaking with thiourea (500 ppm) tended to improve grain yield (13.4 per cent over control), but improvement in biological yield was significant. However, seed soaking plus foliar treatment of thiourea significantly increased both biological and grain yields, besides causing significant improvement in leaf area index and number of green leaves plant^-1. The increase in grain yield ha^-1 was of the order of 34.6 per cent over control.
It was further noted that foliar sprays of thiourea (1000 ppm), thiamine (100 ppm) and ascorbic acid (100 ppm) significantly increased leaf area index, number of green leaves plant^-1 and biological yield ha^-1. These treatments also significantly increased grain yield ha^-1 by 40.6, 20.2 and 26.3 per cent, respectively over control. Improvement in maize yield with thiourea, thiamine and ascorbic acid treatments appeared to have resulted from increased photosynthetic efficiency and canopy photosynthesis on account of the biological activity of -SH group. It was also apparent that leaf senescence was delayed under the influence of these chemicals. It is therefore suggested that thiourea, thiamine and ascorbic acid are the potential bioregulators for improving photosynthetic efficiency and grain yield of maize and possibly other cereals, and that thiourea, a sulphydryl compound, holds considerable promise in this context.     

水稻生育期对籽粒产量及品质的影响

明确水稻生育期与产量、品质的关系,对水稻高产优质育种和合理栽培措施的制定,具有重要的意义。本文以晚粳宁111和春江302经遮光(短日照)处理后获得的不同生育期水稻植株为材料,分析其产量和米质指标。结果表明,生育期152 d以上时,对产量无显著影响,而生育期短于152 d时,产量与生育期间呈极显著正相关;成熟期群体干物质积累量随生育期变化的趋势与产量表现基本一致。不同稻米的长度、宽度、蛋白质含量以及淀粉消减值,均以中等偏短生育期(131~132 d)最小,大于或小于131~132 d,均会使上述指标值增加;两品种直链淀粉含量亦有相似的趋势,只是其最低值分别对应132和137 d的生育期;各处理稻米淀粉的崩解值变化与消减值趋势相反。对垩白粒率、垩白度及糊化温度,各处理均呈随生育期延长而降低的趋势;生育期变化对碾米品质影响总体上较小。     

Stomatal and Non-stomatal Effects of Salinity on Photosynthesis in Faba Beans (Vicia faba L.)

The effect of salinity (40 and 80 meq/1 NaCl) on stomatal conductance, chlorophyll content, ultrastructural damage and photosynthetic performance of six cultivars of faba beans ( Vicia faba L.) from different agroclimatic regions were investigated. Low levels of salinity (40 meq/1 NaCl) increased chlorophyll content in some cultivars but did not lead to simultaneous increase in photosynthesis (P). Increased salinity levels (80 meq/1 NaCl) decreased chlorophyll content and stomatal conductance. Ultrastructural damage was observed in sensitive cultivars even at low salinity levels. Based on the parameters investigated, there was no concrete evidence to suggest that the physiological processes of cultivars from arid and semi-arid regions are less affected under saline conditions as compared to cultivars from temperate regions. The results suggested increased salinity affects P not only due to its effect on stomatal closure but also due to other non-stomatal effects like ultrastructural damage and decrease in chlorophyll content below a threshold level.     

不同有机酸对烤烟品质和产值的影响

采用大田试验研究了苹果酸、油酸和腐殖酸对烤烟品质指标及产值效果的影响。结果表明, 3种有机酸能明显提高烟叶中P素、K素、总糖、还原糖含量、钾氯比和糖碱比值, 以及糠醛、苯甲醛、茄酮、巨豆三烯酮和新植二烯等主要香气成分的含量, 改善烟草的香吃味。同时不同程度地降低烟叶中N素、淀粉、蛋白质、烟碱和氯离子的含量, 从而协调和平衡烟叶中的化学成分, 改善烟叶的品质。其中, 苹果酸的效果最佳, 腐殖酸和油酸次之。苹果酸可明显提高烤烟的均价和上中等烟的比例, 腐殖酸可明显提高烤烟的产量、产值及上中等烟的比例。     

施氮量对油菜氮素积累和运转及氮素利用率的影响

于2010-2012年度以5个不同油含量的常规油菜品种为材料,设置120 (N1)、240 (N2)和360 kg hm^–2 (N3) 3个水平的氮肥处理,在初花期和成熟期取样及定期捡拾田间落叶,测定植株干物质积累量、氮素含量及油含量,研究氮肥水平对油菜氮素积累、运转及氮素利用率的影响。结果表明,随着氮肥用量增加,产量和氮素积累总量增加,氮素收获指数和氮素籽粒生产效率逐渐降低。不同处理叶片氮素运转率变幅为76.6%~80.2%,不同氮肥处理间无显著差异。不同处理茎枝氮素运转率变幅为36.0%~57.6%,随着氮肥用量增加而降低。不同处理落叶氮占植株总氮积累量比例的变幅为14.9%~20.3%,随着氮肥用量增加,落叶氮比例逐渐增加。不同处理初花期氮积累量占植株总氮量的变幅为75.5%~90.5%,随着氮肥用量的增加,其比例逐渐增加。初花期期积累氮素对后期产量形成作用较大,注重前期施肥可促进花芽分化,形成更多的有效角果,有利于获得高产。