Recent progress and future prospects for mechanized harvesting of fruit crops with shaking systems

Mechanized harvesting technologies with shaking systems for fruit industry have been widely investigated and significantly developed over the past several decades which were presented by a large amount of literature.This paper reviews the research and development progress of mechanized harvesting of fruits systematically with a focus on the theoretical study,fruit crop variety,shaking system categories,abscission chemical agents,and their actual applications.Based on the comprehensive review,mechanized harvesting systems for different fruit crops appear multifarious shaking modes with various vibratory mechanisms and structural dimensions.Major advantages in the development of fruit mechanical harvesting with effective vibratory patterns and catching frames provide a series of economic and agronomic benefits,such as reducing labor costs,promoting standardized planting,and increasing productivity.However,fruit injury and tree damage are the main reasons why mechanical shaking systems are rarely used for fresh fruit harvesting because of tenderness and frangibility of the fruit crops.Therefore,more efforts should be concentrated on the innovative shake-and-catch system with suitable frequency and amplitude to achieve low fruit damage or even nondestructive harvesting for fresh fruit market.This overview summarized the advantages and bottlenecks of these shaking systems for fruit harvesting and proposed the challenges and some constructive prospective viewpoints aimed at the major issues of mechanical harvesting techniques.In addition,employing sorting technologies to classify the postharvest fruits provide a new direction for the further development of mechanized harvesting in high-value fruit crops,as well as bring more benefits to growers and increase their interest in equipment investment on the mechanical shaking harvester for the fruit industry.

Applications of CRISPR/Cas genome editing in economically important fruit crops:recent advances and future directions

Fruit crops,consist of climacteric and non-climacteric fruits,are the major sources of nutrients and fiber for human diet.Since 2013,CRISPR/Cas(Clustered Regularly Interspersed Short Palindromic Repeats and CRISPR-Associated Protein)genome editing system has been widely employed in different plants,leading to unprecedented progress in the genetic improvement of many agronomically important fruit crops.Here,we summarize latest advancements in CRISPR/Cas genome editing of fruit crops,including efforts to decipher the mechanisms behind plant development and plant immunity,We also highlight the potential challenges and improvements in the application of genome editing tools to fruit crops,including optimizing the expression of CRISPR/Cas cassette,improving the delivery efficiency of CRISPR/Cas reagents,increasing the specificity of genome editing,and optimizing the transformation and regeneration system.In addition,we propose the perspectives on the application of genome editing in crop breeding especially in fruit crops and highlight the potential challenges.It is worth noting that efforts to manipulate fruit crops with genome editing systems are urgently needed for fruit crops breeding and demonstration.

Recent advances in fruit crop genomics

In recent years,dramatic progress has been made in the genomics of fruit crops.The publication of a dozen fruit crop genomes represents a milestone for both functional genomics and breeding programs in fruit crops.Rapid advances in high-throughput sequencing technology have revolutionized the manner and scale of genomics in fruit crops.Research on fruit crops is encompassing a wide range of biological questions which are unique and cannot be addressed in a model plant such as Arabidopsis.This review summarizes recent achievements of research on the genome,transcriptome,proteome,miRNAs and epigenome of fruit crops.

Branched Secondary Alcohol Ethoxylate, Ammonium Thiosulfate, Calcium Polysulfides-Thiosulfate, and Fish Oil Effects on Blossom Thinning, Fruit Set and Quality of Peaches and Nectarines

Total crop load has an inverse relationship with fruit size, while larger fruit size is often demanded by the peach and nectarine markets. Hand-thinning is extremely expensive, and thus, crop load adjustment, using blossom thinners is a crucial practice to ensure production of commercially acceptable fruit size and yield efficiency in stone fruit. In this study, the influence of branched secondary alcohol ethoxylate (Tergitol TMN-6) and/or ammonium thiosulfate (ATS), Crocker Fish Oil (FO), and a mixture of calcium polysulfides and thiosulfate (lime sulfur) on fruit set and quality attributes in peaches (Prunus persica) and nectarines (P. persica var. nectarina) were studied. All blossom thinners reduced fruit set in “Summer Lady” peach in both 2016 and 2017. Fruit sets in “Summer Lady” peach trees with a double application of Tergitol TMN-6 at the rate of 7.5 or 10 mL ·L¯1, each rate applied at 40% and 80% bloom, were lower than those receiving the same rates of this chemical only at 80% bloom, but they were similar to those receiving a single Tergitol TMN-6 spray at 15 mL·L¯1 at 80% or 100% bloom. “Summer Lady” peach trees receiving FO at 20 mL·L¯1 plus lime sulfur at 25 mL·L¯1, once at 40% bloom and again at 80% bloom had lower fruit set as compared to Untreated Control but the fruit set was higher than those with any Tergitol-TMN-6 spray. Tergitol TMN-6 at 12 m·L¯1 at 100% bloom or 10 mL·L¯1 all stages of bloom reduced fruit set in “Zee Lady” and “Snow Giant” peaches. In “Snow Giant” peach, trees receiving Tergitol TMN-6 at all concentrations and blossom stages had significantly higher fruit weight as compared to the trees of Un-treated Control. Applications of Tergitol TMN-6 at all concentrations at 80% bloom reduced fruit set in “Red Globe” and “Elberta” peaches in Utah. ATS and FO slightly reduced fruit set in peaches but they were less effective than Tergitol TMN-6 in all cases. Overall, it is concluded that efficacy of blossom thinners depends on the rate of thinners, temperature, cultivar and stage of bloom development.

Growth simulation and yield prediction for perennial jujube fruit tree by integrating age into the WOFOST model

Mathematical models have been widely employed for the simulation of growth dynamics of annual crops,thereby performing yield prediction,but not for fruit tree species such as jujube tree(Zizyphus jujuba).The objectives of this study were to investigate the potential use of a modified WOFOST model for predicting jujube yield by introducing tree age as a key parameter.The model was established using data collected from dedicated field experiments performed in 2016-2018.Simulated growth dynamics of dry weights of leaves,stems,fruits,total biomass and leaf area index(LAI) agreed well with measured values,showing root mean square error(RMSE) values of 0.143,0.333,0.366,0.624 t ha^-1 and 0.19,and R2 values of 0.947,0.976,0.985,0.986 and 0.95,respectively.Simulated phenological development stages for emergence,anthesis and maturity were 2,3 and 3 days earlier than the observed values,respectively.In addition,in order to predict the yields of trees with different ages,the weight of new organs(initial buds and roots) in each growing season was introduced as the initial total dry weight(TDWI),which was calculated as averaged,fitted and optimized values of trees with the same age.The results showed the evolution of the simulated LAI and yields profiled in response to the changes in TDWI.The modelling performance was significantly improved when it considered TDWI integrated with tree age,showing good global(R2≥0.856,RMSE≤0.68 t ha^-1) and local accuracies(mean R2≥0.43,RMSE≤0.70 t ha^-1).Furthermore,the optimized TDWI exhibited the highest precision,with globally validated R2 of 0.891 and RMSE of 0.591 t ha^-1,and local mean R2 of 0.57 and RMSE of 0.66 t ha^-1,respectively.The proposed model was not only verified with the confidence to accurately predict yields of jujube,but it can also provide a fundamental strategy for simulating the growth of other fruit trees.

Indigenous Fruit Trees of Tropical Africa: Status, Opportunity for Development and Biodiversity Management

Tropical fruit trees constitute important biological resources in the global agrobiodiversity context. Unlike the tropical fruit trees of American and Asian origin, indigenous fruit trees (IFT) of tropical Africa have scarcely achieved the status of international recognition in commodity markets and research arena outside Africa. This paper presented a critical review of the status of IFT in the Tropical African sub-regions (of West Africa, Central Africa, East Africa, Southern Africa and the Indian Ocean Islands) in relation to the introduced naturalised fruit trees from tropical America and Asia, threats to the diversity and sustainable use of IFT, analysis of the opportunities and challenges of developing IFT, as well as targets for crop improvement of the rich IFT of Tropical Africa. Domestication programme via relevant vegetative propagation techniques for priority IFT of the sub-regions was examined and advocated, in addition to the adoption of complementary conservation strategies, including Field GeneBanks in the management of the continent’s IFT diversity.

不同节位修剪对‘夏黑’葡萄二次花芽分化及果实品质的影响

为研究‘促早+避雨’栽培模式下,不同节位修剪对葡萄二次成花及二次果果实品质的影响,以7 a生‘夏黑’葡萄为材料,分析留5芽、留7芽和留9芽(简称5芽、7芽、9芽)修剪对葡萄萌芽率、成花率、单果质量、穗重、可溶性固形物含量等指标的影响。结果表明:3种不同修剪方式对葡萄二次萌芽率和成花率均产生了一定影响。其中,5芽修剪萌芽率和成花率最高,9芽修剪则较低。在单果质量和穗重方面,5芽修剪二次果穗重最大,但不同节位修剪并未对单果质量和果形指数产生显著影响。5芽和7芽修剪二次果可溶性固形物含量显著高于9芽修剪,5芽修剪二次果可滴定酸含量则显著低于9芽修剪,5芽修剪二次果葡萄糖和果糖含量均显著高于9芽修剪,但不同节位修剪均未对蔗糖和花色苷含量产生较大影响。综上所述,3种修剪方法中留5芽修剪最适宜于‘夏黑’葡萄一年两熟栽培,其次为留7芽修剪,留9芽修剪则不太适宜。

园艺作物果实β-半乳糖苷酶研究进展

β-半乳糖苷酶属于糖苷水解酶GH35家族,参与了植物不同生长阶段细胞壁的合成与修饰,尤其对肉质水果发育和成熟过程中多糖的裂解具有重要作用。文章概述了β-半乳糖苷酶的蛋白功能、不同亚型、亚细胞定位和活性规律,重点阐述了该基因家族在园艺作物果实质地变化中的作用及相关研究进展。

不同处理对大棚草莓连作土壤理化性质和果实品质的影响

为了探讨不同处理对大棚草莓连作土壤和果实品质的影响,以未处理为对照(CK),研究了甜玉米轮作、棉隆消毒、生物炭利用、菌渣混土等7个不同修复技术对处理后土壤理化性质、植株生长、果实品质、产量的影响。结果表明:甜玉米轮作处理(T1)土壤含水量、容重最高,EC值最低,养分含量除了全氮、全钾、碱解氮、有效锌外最低,盐分离子含量均低于CK;小麦秸秆炭处理(T3)土壤含水量、容重较低,EC值最高,pH值高于CK,有机质、全磷、有效磷、有效铜、有效锌含量最高,盐分离子含量除了F-和Cl-外均高于CK;T1草莓植株生长指标高于CK,单果重、单株产量高,果实硬度大,可溶性固形物含量高,糖酸比、固酸比最高。综上所述,T3可有效改善土壤板结和酸化,减少养分损失;T1土壤保水性好,养分利用率高,可消耗部分过多养分,减轻土壤富营养化,减缓连作土壤次生盐渍化,促进植株健康生长,提高果实品质和产量。

轮作与配施有机肥对菠萝生长、果实品质及产量的影响

通过田间试验,研究轮作与配施有机肥对菠萝生长、果实品质与产量的影响。结果表明:与菠萝连作(PP)处理相比,菠萝连作配施生物有机肥(PPB)、菠萝-甘蔗轮作(PS)、菠萝-甘蔗轮作配施生物有机肥(PSB)处理可显著促进菠萝生长、提高果实产量和品质。在植株生长方面,PPB、PS及PSB处理对叶长、叶宽及叶片数有显著的促进作用;在果实外观方面,果实纵径、横径、果眼数、果肉厚度、果肉厚度/果心直径比显著增加,而顶芽高与果心直径显著下降;在果实品质方面,可溶性固形物、维生素C及可溶性糖含量显著提高,可滴定酸含量明显降低;在产量方面,平均单果质量分别显著增加32.61%、51.09%和71.74%,总产量分别显著增加14.74%、34.58%和48.28%。此外,PSB处理的产量、果实性状及品质指标显著高于PPB处理,且优于PS处理。建议当地发展菠萝时,可在菠萝-甘蔗轮作基础上,适当配施生物有机肥。

不同土壤处理对重茬地苹果幼树生长结果的影响

重茬栽培存在重茬障碍问题,严重影响苹果幼树的生长发育。作者研究不同土壤处理对重茬地苹果幼树生长结果的影响。结果表明,不同土壤处理均有较好效果,明显提高果树成活率、促进树体生长发育、提高果实产量和品质。其中,多菌灵+菌肥、棉隆熏蒸+菌肥、客土3个处理的效果最好,可在实际生产中推广应用。

水分胁迫对果树光合作用及同化代谢的影响研究进展

综合有关文献从水分胁迫对果树的净光合速率、干物质积累和分配、气孔反应、光抑制、光合色素、光合酶活性、氧化物质代谢、呼吸以及叶绿素荧光等几个方面的影响进行了分析总结。并认为今后应加强多因子相互作用、多循环胁迫的研究;还应扩大研究对象,筛选适宜的树种(品种)和抗水分逆境的生理指标;同时还要加强与呼吸作用和荧光反应生化分析等方面研究的结合。

落叶果树需冷量及其机理研究进展

落叶果树需冷量的准确估算是果树栽培尤其是果树促成栽培中的一个关键因素,直接关系到果树促成栽培的成败。综合有关文献,介绍了落叶果树需冷量的概念、估算方法、研究现状、生物学机制和存在问题。低温可以诱导休眠,休眠解除需要低温积累,从植物生理学和分子生物学角度阐述了落叶果树需冷量的机理。并对缩短落叶果树自然休眠期的可能途径从育种、施用外源化学药剂、环境调控3个方面进行了初步探讨。

矮生樱组3个野生种果实性状的变异

对分布于山东胶东昆嵛山区的欧李、麦李及郁李3种野生樱桃207个实生单株果实性状的变异进行了初步研究,旨在为资源的保护与利用提供科学依据。结果表明:(1)欧李和麦李果实成熟期主要集中在7月中、下旬,个别早熟或晚熟类型的果实成熟期分别在7月初和9月中下旬,而郁李果实成熟期主要集中在9月份,个别晚熟类型在10月下旬成熟;(2)3个种果实(果核)纵径和横径及果(核)形指数在种内的变异系数均小于15%,是相对稳定的植物学性状;(3)单果质量、果柄长度、果实Ca与可溶性固形物含量在种内不同类型间存在较大的遗传变异,变异系数均在20%以上,遗传多样性极为丰富。

我国果树多倍体育种研究进展

综合有关文献对主要果树多倍体的现状、果树多倍体育种的途径及其取得的成就、果树多倍体的鉴定、果树多倍体育种中应注意的问题进行了系统的阐述。果树多倍体育种的途径主要有利用对自然变异的选择获得多倍体、利用人工诱变获得多倍体、利用有性杂交培育多倍体、利用胚乳培养获得多倍体和利用原生质体融合培育多倍体;对多倍体的鉴定可以从形态特征、解剖结构、生理生化特性和染色体数目观察等方面来考虑;在今后的果树多倍体育种中应注意确定合适的倍性作为育种目标、重视多倍体种质资源的创新与应用、重视对多倍体嵌合类型的分离纯化、注意利用现代新技术提高育种效率、要加强对多倍体育种中有关问题的研究。

盐胁迫对果树光合生理的影响

结合我们相关的研究结果综述了盐胁迫对果树光合作用的影响。总体来说盐胁迫导致果树净光合速率下降,且这种作用受树种、品种、砧木以及盐的种类、浓度和处理时期的影响;盐胁迫还使叶片干物质积累下降并影响碳水化合物的组成。盐逆境所产生的渗透胁迫和离子毒害而引起的气孔性限制和非气孔性限制则是果树叶片净光合速率下降的原因。此外,盐胁迫使果树叶片的叶绿素荧光效率下降。文章最后还提了出今后研究果树盐胁迫与光合作用的关系应与实际的生产环境相结合。

赤霉素在落叶果树生产中的应用

赤霉素在落叶果树上应用范围很广,具有诱导无子果实的形成、提高座果率、改善果实品质、防止落花落果、促进果实早熟、延迟果树花期、增加果品贮藏能力和打破休眠的调控作用。文章对其研究进展和作用机理进行了简要概述。

一种木本果树基因组DNA提取方法研究

研究了一种可有效排除细胞内多酚类等杂质污染的简便、快捷、经济的果树基因组ＤＮＡ提取方法．其改良策略是：在细胞核被裂解前去除细胞质中的多酚类等杂质，防止多酚类物质被氧化，从而排除多酚类等杂质的干扰．利用这一方法提取的柑桔、枇杷、梨、苹果、湖北海棠、桃、樱桃等７种果树基因组ＤＮＡ均能被限制性内切酶完全消化，获得理想的Ｓｏｕｔｈｅｒｎ杂交结果，也可作为ＰＣＲ模板应用，成功地进行特异性基因扩增和ＲＡＰＤ．

胚抢救技术在果树上的应用

胚抢救技术在果树早熟、无籽、三倍体类型育种及获得远缘杂种、阻止胚早期退化和缩短育种周期等方面具有重要作用。对胚抢救技术在果树作物育种中的应用及取得的成绩作了综述，并对胚抢救中应注意的几个问题，如适宜的培养时期、营养及环境条件作了简介，同时初步提出了果树胚抢救技术存在的不足及今后的研究方向。

果树远缘杂交育种研究进展

远缘杂交是指种或属间及亲缘关系更远的分类单位间进行的杂交,它是创造果树新种质的重要途径。简要列举了果树远缘杂交育种取得的主要成就,阐述了远缘杂交不亲和和育性障碍的若干表现与机制。目前克服杂交障碍的途径有:蕾期授粉、混合花粉、重复授粉、亲本选择、特殊处理、胚抢救和染色体加倍等。杂交后代遗传变异分为3种类型:综合性状类型、亲本性状类型和新物种类型。杂交后代的早期鉴定方法有形态鉴定、染色体鉴定、同工酶鉴定和分子鉴定。果树远缘杂交育种虽然困难很多,但前景非常广阔,今后的重点是深入研究远缘杂交不亲和和育性障碍的机理和有效的克服途径,并借助分子标记技术对杂种进行早期鉴定以及对复杂遗传规律进行深入研究。