板栗切口机设计 (2)【cad高清图纸和说明书全套】
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河北科技师范学院本科毕业设计外文翻译板栗切口机的设计院(系、部)名 称 : 欧美学院机电科学与工程系 专 业 名 称:机械设计制造及其自动化 学 生 姓 名: 刘振 学 生 学 号: 9313110220 指 导 教 师: 刘长荣 2014年12月10日河北科技师范学院教务处制河北科技师范学院2015届本科毕业论文(外文翻译)美国板栗产业罗伯特C.霍赫穆特、罗伯特华莱士、彼得 J.van Blokland 和 Jeffrey G.威廉姆森这是原始文件的修订副本,介绍了生产,销售,和栗子生长在东南亚美国的情况,通过RD华莱士和PJ VanBlockland。佛罗里达大学的1989年,食品资源经济系。工作人员报告。1序言美国是少数几个国家在世界上能生长栗子和不具有显著的商业板栗产业之一。因为美国有板栗产业这样一个小的(世界产量的不到1)产业,进口到美国的栗子的数量与每年的总价值超逾2千万元。新的栗子品种开发,先进的传播,文化的技术现在允许美国扩大在商业板栗产业。栗子可就在佛罗里达州小农谁正在寻找他们的业务多元化,一个可行的替代作物。2历史农作物有很多的历史重要性,因为世界各地的食物来源如栗子。栗子是最早木本作物被驯化了,甚至在中国诗歌中提到5000余年前的一个。北美的欧洲殖民者发现的新大陆几乎是一个坚实的板栗林。美国栗树曾经在东部森林中最常见的树木中,从缅因州到乔治亚州,西至密西西比河。这个令人惊讶的有用的树提供防腐性木材,这是用于几个项目,从栅栏柱到家具。板栗树也是单一的来源,除了其美丽的坚果作物。但是从东方在1904年意外引入的栗疫病(栗疫病菌),在不到40年杀害了几乎所有的美国栗树在美国。在美国板栗的损失被认为是西方历史上最伟大的植物灾害之一。板栗产业高度发达的欧洲,在世界的东方。韩国和中国是板栗产业发达的两个国家;同时这些国家产生超过40的世界栗子。其他主要的板栗生产国包括意大利,土耳其,玻利维亚,日本,西班牙和葡萄牙。栗子对美国的主要出口国是意大利,中国和韩国。板栗进口到美国的4,500吨增加到2003年的5,400万吨,2004年同比增长,表明栗子在美国的消费者的需求在不断增长。进口到美国的栗子每年的价值超过2000万美元。 这是抗栗疫病和生产大,甜坚果 - - 新美国x中国杂交板栗品种的发展有助于使国内板栗产业在美国可能的扩展,包括在佛罗里达州。新板栗品种具有毫不逊色与进口坚果竞争的高品质特性。然而,美国商业板栗产业是相对较新;大多数种植者有不到10年的经验。为板栗生产大国,包括加利福尼亚州,俄勒冈州,华盛顿州,密歇根州,佛罗里达州,俄亥俄州和弗吉尼亚州。3 板栗经济学栗子可以是生产力和盈利果园作物。树木开始后三到五年来承担,而改良品种可以在到期日,从1000 - 1,500斤以上的产量每亩每年。螺母从$0.75-2.50元一斤批发,(根据螺母的大小)和$2-5.00元一斤零售,供给取决于市场。 国产栗子的市场一直主要通过本地或直接的市场销售方式。一些美国种植者通过互联网在超过10美元每磅小批量的价格做广告的新鲜栗子,但这个价格包括联邦快递或UPS运费和手续费。本地的,直接面向消费者的销售可能高达$4.00或5.00元一斤,但这样的价格在销售大幅下降到经纪人,批发商,连锁超市等大型市场。美国种植栗子数量大,价格必须要与进口坚果竞争力,和美国生产的质量必须优于质素的外国买家,他们的美国客户都习惯。 在美国种植栗子作物有达到美国市场早于进口的栗子,用更好的质量控制,并没有国际航运的成本优势。然而,在移动大量栗子的成功的关键是通过市场营销,消费者和经销商的教育,并与有识之士在食品配送服务关系的发展。营销是没有过去存在的小种植者很多机会,现在可以通过互联网,但有针对性的市场推广力度,食品行业也可以是非常有价值的。生长在美国的四种栗子和他们几个杂交种品种美国栗子(板栗齿。)有小的,甜的坚果,直立生长形式,极易受到栗疫病。欧洲栗(Catanea)也枯萎病易感,且只能在疫病非疫区生长。欧洲板栗树有一个直立的树的形式,并从欧洲栗子的坚果可以是相当不错的一些品种。然而,许多品种及种苗生产坚果的味道平淡,或苦,难以剥离。中国板栗(板栗)是高度抗枯萎病,有些品种产生良好的规模和甜蜜味道也很容易剥离的坚果。中国板栗树,有时在生长形态挺拔,但很多是低,传播和多支在地上。日本栗子(板栗籽)粒小,传播,产生较大的,可怜的品尝坚果抗枯萎病树。日本栗子大多用于杂交。Chinkapins(数种)生产小型,甜坚果(每毛刺之一),通常是灌木状的形式,不用于商业螺母生产。在栗属的成员的关系非常密切和杂交的容易。杂交提供了一些有前途的商业品种中最有潜力的。在欧洲,大部分板栗育种已经完成,日本x欧洲的杂交品种。在日本和韩国,多数商业化生产的今天与中国x日本杂交品种。在美国,一些最近开发的美国x中国混合动力车提供的特点,优秀的商业品种为佛罗里达的组合。图1。 美国x中国杂交板栗树。5螺母的质量和档次大小:在任何品种的一个主要关注的是生产螺母的大小。对于营销到一个新的或预先包装市场中,大尺寸是必需的(图2)。虽然美国农业部门(USDA)没有采用任何标准的栗子大小,在2001年提出由美国农业部以下尺寸的标准(表1)。图2。 客户喜欢较大的个体坚果。进口商有时用于基于每磅坚果的数目(表2)大小的标准。坚果超过每磅40支小的都很难通过大规模的营销系统(经纪和食品杂货连锁店)来分发,因为美国的渴望更大的板栗大小(图3)中。小栗子一般都是在美国市场不太理想的,并带来了更低的价格。然而,如果该栗子用于烘干,面粉或糖果,大小并不重要。图3。 各种螺母尺寸板栗品种之一。味道:味道也很重要。有些品种具有较高的含糖量,甚至生吃。栗子中的碳水化合物转成糖的坚果成熟和干燥。栗子烹调前固化是很重要的,衬托出坚果的味道。美国栗树是相当甜美的。一些中国的栗子和美国杂交种有非常甜美的坚果。一些欧洲和中国的品种,通过比较,而不是甜的。易于剥离:重要性的第三螺母的特点是容易剥离的螺母。该薄膜或“皮肤” ,围绕内核是苦,吃之前必须拆除。在某些类型的栗子,胶片被嵌到内核中,这使得螺母难以剥离,因此,不良的饮食质量的粗糙表面。许多欧洲栗子有这样的不良特性。在法国区分栗子的基础上,容易剥离的类型之间。栗子,栗子原产于地中海,有表面光滑的内核,很容易剥离,并具有向内生长的薄膜。该种栗子以更高的价格在法国和美国的商店出售,但是这两种类型的板栗运到美国,他们是美国消费者的青睐。美国和中国的栗子,其杂交种往往有流畅的内核和更容易剥离。容易剥离是重要的商业处理,以及用于接受消费者;内核一点点消失在剥离过程中,那很容易去皮栗子需要少得多的时间和费用,除去药膜。6繁殖主要类型在今天的美国销售的板栗树是中国板栗苗。中国苗栗子一般都是可变的螺母尺寸,口味,树形态和生产力。该树结的3-8年,远远晚于嫁接树种。在某些情况下,比嫁接树更耐寒更加旺盛。栗子在美国的大多数现有的种植面积是苗。在作物的质量很大的可变性降低板栗的销路。 嫁接和芽接繁殖是对栗子的克隆最常见的方式。 栗子有时会受到砧木/接穗不亲。造成这种不兼容的因素是生态和遗传。接穗嫁接到砧木具有不同的同工酶可能会显示活力差,不一致的农作物,甚至死亡的移植物上面的接穗。移植物在非常寒冷的气候或严重发热或干旱后失败了。生长环境:栗子可以生长在各种气候条件和环境中,但适合种植桃子的范围通常被认为是适于生长的许多板栗的栽培品种。栗子也遍及用于山核桃生产领域在佛罗里达州生长良好。生产坚果的最佳条件包括温暖和相对较长的生长季节和温和的冬天。灌溉是建议最大的螺母生产尤其重要的果园初步建立。虽然栗子花下旬,春季霜冻可能会损坏新的成长新芽,并应避免低洼霜口袋。栗子喜欢pH值5.0-6.5,排水良好的高地沙壤土。土壤不应该受到积水和/或定期泛滥。如果机械收割机的使用,在野外太多斜坡在使用机器造成困难,而且潮湿的土壤条件,秋雨可以通过果园抑制方便移动。北佛罗里达特别适合于不断增长的栗子。从奥兰多向北穿过佛罗里达狭长地带的领域包括板栗种植已成长为超过40年。果园种植和生产:树苗间距差异很大取决于品种。然而, 20*20 ( 108株/亩)是常见的。这个间距产生了树木的紧密堆积之间的最佳平衡,以提高早期生产的果园和需要薄树的作为冠开始触摸。栗子需要水分和肥料的管理良好的供应。滴灌建议节约用水,有效地提供水源的树木而已,而不是杂草在非作物区行之间。施肥方案应根据土壤测试。然而,一个常见的应用栗树是1磅10-10-10或每树龄高达15磅每棵树在春天应用年类似的分析。灌溉施肥,或频繁通过滴灌系统饲养,是有效的,与营养物质的浸出损失较少促进增长。栗子是沉重的馈线和氮是正确的快速增长尤其重要。像许多槟榔树,栗子启动缓慢,需要2-3年才能完全建立。毛刺应在第一个三年中删除,以更好地促进树木生长。大多数板栗果园类似山核桃的方式管理,用干净的栽培下两行之间的行和草皮覆盖作物。年轻的板栗果园可间作一行作物,如花生常年,三叶草,草或小水果作物,直到板栗收获开始在5年后种植。7 修剪栗子承担对两性的柳絮(纤细,圆柱形的花簇) ,这是位于目前的年新梢生长的基地附近。增长的新丫发生在太阳光的地方,在树枝的顶端。修剪应尽量阳光提供给树的数量。开放式中心树(如桃树),让阳光照进花瓶形的中间,以及顶部和两侧。欧洲的果园和日本和韩国的果园修剪以这种方式。 苹果,山核桃,胡桃常用修剪系统产生 - 创建一个锥形树已经支承表面都绕锥的外侧。这种方法也可以接受的栗子使用。直立的树木更好地应对机械震动以去除坚果。非常分散的树木可能会更加难以摆脱的坚果,因为树枝倾向于下垂,增加了振动筛的振动。证据也表明,较小的树可能比那些太高,易于收获更可取和修剪,随着遗传特征,将是重要的在确定最终的树的形状和大小。许多小的树板栗品种产生了良好的佛罗里达很少修剪。8果园害虫管理栗子有几个严重的害虫。板栗疫病(栗疫病菌)主要由枯种植抗性品种淘汰。只有抗枯萎病树应考虑种植在佛罗里达州。墨疾病,疫霉根腐病菌,已在美国东南部的一个问题,但可以通过果园地面管理控制,保持土壤排水良好,不受潮湿的环境,这对促进感染。墨一直是一个问题在欧洲和美国的太平洋海岸,在那有长,潮湿的冬天领域。鹿和松鼠可以在栗子常见的野生动物害虫。鹿围栏可以是必要的,如果鹿是本地的害虫,以及可能需要的螺母的收获如果松鼠或鹿是问题。板栗象鼻虫(象鼻虫),奠定了在发展中的坚果卵,和成熟的坚果有虫在里面收获成长,导致坚果变成滞销。象鼻虫花,冬天地上树下的蛹。很少有农药被标记为板栗象鼻虫的控制权,所以卫生习惯是关键。收获完成后,收集所有多余的毛刺,坚果和树叶杂物和可能的话烧灭。东方栗瘿蜂(栗瘿蜂)是一种严重的害虫,形成虫瘿在不断发展板栗芽,从而停止螺母生产。生物和化学控制是尚未无效的这个黄蜂,但是一些韩国品种展示抵抗黄蜂。强烈建议不要从那里瘿蜂虫害发生地区的移动板栗树或材料。授粉和螺母形成:栗子是雌雄同株;男性和女性的花着生在同一棵树上(图4)目前的季节芽。鲜花出现在当前季节增长的秘诀,后叶子已经完全展开,和足够的后期,以避免(5月上旬至中旬在美国佛罗里达州)任何晚春霜冻。栗子是自育(不会自花授粉),因此,需要授粉。不完全授粉,将导致仅在一个或两个螺母形成的毛刺的内部;剩下的坚果也不会填写。栗子主要是风授粉的昆虫,虽然也可能有助于授粉。树应以至少8:1品种种植。嫁接树开始承担在两到四年,种苗将承担五至七年。延迟生产的嫁接树很可能会发生,因为授粉树不开花充分早年(种植后第三年至第五年)。图4。 雄花和雌花在同一棵树上。螺母的发展,并填写主要发生在过去两到三个星期后熟(图5)之前。螺母在这段时间获得其大部分重量,而且由于坚果是40的水和40的碳水化合物,一个良好的水供应,无论是从季节性降雨或灌溉,是最大限度地提高螺母的生产至关重要。从开花到采收时间从110-150天不等,视品种。作为坚果成熟,毛刺开始裂开,并且螺母被释放的毛刺或飞边落在从树的坚果还在里面(图6)。图5。 苞(中心),成熟的栗子(左)和未成熟的栗子(右)。图6。 板栗毛刺裂接近收获的季节。9采收和储藏栗子的收获是传统上用手工劳动完成的,其中,在小果园,可以比机械收获更有效。因为栗子是高碳水化合物,它们衰变迅速,必有收获每隔两到三天消除的时间花在坚果在地面上的金额。栗子的机械收割是大致相同的山核桃,杏仁,核桃或行业。振动器是成功的,因为从树上将毛刺去除的手段。螺母和毛刺可以被收集,无论是在catch框架或在树下地面网状网,或是坚果可以拿起各种机械山核桃收割机或设计用于其他坚果作物收割机。一旦从果园收集,螺母和毛刺是分开的,并且将螺母直接进入冷却器。该毛刺是通过去毛刺装置,诸如那些用于除去胡桃的壳,或山核桃吸尘器运行。绿色毛刺与不发达坚果(尚白)可以单独举行,直到成熟的坚果在数天。螺母洗涤,然后按大小分级,并存储在紧密编织的,但透气网袋在32华氏度和85的湿度。栗子将持续长达半年,当这些条件下储存。在较高温度下,将螺母将衰减比,因为在较低温度下更高的生物活性的更快。高湿度是必需的,因为坚果会脱水,失去其质量在大多数冷却器。快速浸( 45-60分钟),热水( 125O F)可以杀死许多腐烂的有机物和板栗象鼻虫幼虫。热水浸渍后,将螺母在冷水中冷却,然后存储在32O F。处理整个栗子,可去皮罐装或冷冻。这种处理通常增加了产品的货架寿命比新鲜坚果和,更重要的是,降低了消费者的劳力和时间的制剂的量。添加到去皮和包装产品的价值是巨大的,可能是重要的在增加栗子的市场规模,尤其是增加使用的螺母超越传统栗子的季节,感恩节和圣诞节。预打包为适应栗子美国市场的一个非常重要的考虑因素。 机械可用于机械剥离和包栗子。去皮,冷冻栗子将保留他们的口味长达两年。栗子也可以晒干后磨成面粉。在欧洲和东方,栗子粉早已高度在做面包,面食和糕点珍贵的甜味。特产板栗产品正变得越来越普遍可在美国市场,并通过网络销售。市场营销用于在美国长大许多坚果发达的配送系统也可用于在这个国家种植栗子。种植者与大型,高品质的栗子可与进口的栗子作物有利竞争,因为国内的种植者可以达到美国市场的时间较早,并提供一个新鲜的产品,因此,卖出高价。有在美国种植优质板栗许多有潜力的市场。美味和健康食品市场和餐馆提供的网点,消费者通常在尝试和学习新的食品产品的兴趣。民族法语,意大利语和东方市场已经携带板栗产品,有兴趣找本地的,高品质的栗子来源。几乎所有的连锁超市进行进口栗子在感恩节和圣诞节。当地社区农贸市场正变得越来越受欢迎,在佛罗里达州,并作为出口市场的坚果。网络销售也可以是一个成功的方法卖栗子和栗子的产品。9营养栗子是一种高营养的食物。与大多数坚果,这是高脂肪(山核桃和核桃) ,栗子只有一丝赘肉,三分之一其他坚果,如花生或腰果的热量。栗子也有显著量的维生素C的唯一螺母和无胆固醇。栗子的蛋白质品质优异和可比较的氨基酸含量是鸡蛋的。栗子被认为是“一个粮食,生长在树上, ”是类似的营养糙米。栗子好吃,并且可以在各种不同的方式,包括在火上烤或清蒸在汤,炖菜,蛋奶酥,开胃馅料和甜点的使用做好准备。栗子可干燥后制成的面食或甜面粉糕点和面包。菜泥或蜜饯,板栗是全欧洲最喜欢的甜点。用途和很高的营养品质,从多年生木本作物这种多样性所做的栗子一种流行的食物来源,包括整个历史以及在世界各地的许多不同的文化。表:表1中。 美国农业部于2001年提出的标准,栗子成绩。大小分类最小直径 (英寸)最大直径 (英寸)猛犸1 3/8不是最大巨型1 1/411/2 巨人11/813/8 大11 1/4表2基于每磅坚果的数量板栗大小标准等级坚果/磅级号码 A36-39AA27-30AAA22-24AAAA19-20AAAAA18或更小脚注1 :这份文件是HS1155 ,由一系列的园艺科学系和佛罗里达州合作推广服务,食品和农业科学研究所,美国佛罗里达大学之一。首次由爱迪斯出版于2009年,2012年8月评论,这是原始文件的修订副本,栗子成长在南方的介绍到生产,市场营销,经济学,由RD华莱士和PJ VanBlockland 。佛罗里达大学的1989年,食品资源经济系。工作人员报告。2 :罗伯特C. Hochmuth ,多县扩展代理,萨旺尼谷农业推广中心;罗伯特D 华莱士,商业种苗,栗山苗圃,阿拉楚阿,佛罗里达州;彼得范Blokland ,教授,食品和资源经济学,印度河流域研究和教育中心,和Jeffrey G.威廉姆森教授,园艺科学系,美国佛罗里达大学。盖恩斯维尔,佛罗里达州32611 。食品和农业科学研究所(独立财务顾问)提供平等机会的机构授权只对与相对于种族,信仰,肤色,宗教,年龄,残疾非歧视性功能的个人和机构提供研究,教育信息等服务,性别,性取向,婚姻状况,国籍,政治观点或隶属关系。有关获取其他UF / IFAS延长出版物的更多信息,请联系您所在县的UF / IFAS扩展办公室。农业, UF / IFAS推广服务,佛罗里达大学IFAS ,佛罗里达州AM大学合作推广计划,以及县委员的合作委员会的美国能源部。尼克T.广场,院长UF / IFAS扩展。本文来自http:/www.renrendoc.com/p-316064.htmlProduction and Marketing of Chestnuts in the Southeastern United States1Robert C. Hochmuth, Robert D. Wallace, Peter J. Van Blokland, and Jeffrey G. Williamson2This is a revised copy of the original document, An Introduction to Production, Marketing, and Economics of Growing Chestnuts in the South East United Sates, by R.D. Wallace and P.J. VanBlockland. 1989. University of Florida, Dept of Food Resource Economics. Staff report. #354IntroductionChestnuts (Castanea sp.) are represented by several species of trees in the beech family (Fagaceae). The chestnut is native to warm, temperate areas the Northern Hemisphere.The United States is one of the few nations in the world that can grow chestnuts and does not have a significant commercial chestnut industry. Because the United States has such a small (less than 1 percent of world production) chestnut industry, chestnuts are imported to the United States in quantities with total annual value exceeding $20 million. Development of new chestnuts cultivars, advances in propagation, and cultural techniques now allow for expansion of the commercial chestnut industry in the United States. Chestnuts may make a viable alternative crop for small farmers in Florida who are looking to diversify their operations.HistoryFew tree crops have as much historical importance as a food source throughout the world as do chestnuts. Chestnuts were one of the earliest tree crops to be domesticated and were even mentioned in Chinese poetry more than 5000 years ago. The European settlers of North America found the New World was virtually one solid chestnut forest. The American chestnut was once among the most common trees in the eastern forest, from Maine to Georgia and west to the Mississippi. This amazingly useful tree offers rot-resistant lumber, which was used for several items, from fence posts to furniture. The chestnut tree was also a source of tannin, in addition to its beautiful crop of nuts. But the accidental introduction of the chestnut blight (Cryphonectria parasitica) from the Orient in 1904 killed almost every American chestnut in the United States in less than 40 years. The loss of the chestnut in the United States is considered one of the greatest botanical disasters in Western history. The chestnut industry is highly developed in Europe and in the Orient. The Republic of Korea and China are the top two countries for chestnut production; together these countries produce more than 40 percent of the worlds chestnuts. Other major chestnut-producing countries include Italy, Turkey, Bolivia, Japan, Spain, and Portugal. The primary exporters of chestnuts to the United States are Italy, China, and The Republic of Korea. Chestnut imports to the United States increased from 4,500 metric tons in 2003 to 5,400 metric tons in 2004, an increase that indicates the growing demand for chestnuts among U.S. consumers. The annual value of chestnuts imported to the United States is more than $20 million. The development of new American x Chinese hybrid chestnut cultivars - which are resistant to chestnut blight and produce large, sweet nuts - have helped to make possible expansion of the domestic chestnut industry in the United States, including in Florida. The new chestnut cultivars have high-quality characteristics that compete favorably with the imported nuts. However, the commercial U.S. chestnut industry is relatively new; most growers have less than 10 years of experience. Major states for chestnut production include California, Oregon, Washington, Michigan, Florida, Ohio, and Virginia.Chestnut EconomicsChestnuts can be a productive and profitable orchard crop. Trees begin to bear after three to five years, and improved cultivars can, at maturity, produce from 1,000 - 1,500 pounds or more per acre every year. The nuts bring from $0.75-2.50 per pound wholesale, (depending on nut size) and $2-5.00 per pound retail, depending on the market. Marketing of domestic chestnuts has been primarily through local or direct market sales methods. Some American growers advertise fresh chestnuts via the Internet at prices of more than $10 per pound in small quantities, but this price includes FedEx or UPS shipping and handling. Local, direct-to-consumer sales may be up to $4.00 or 5.00 per pound, but such prices decrease considerably in sales to brokers, wholesalers, grocery chains, and other large markets. To move American-grown chestnuts in large quantities, prices must to be competitive with imported nuts, and quality of American production must be superior to the quality to which foreign wholesale buyers and their American customers are accustomed. Chestnuts crops grown in the United States have the advantage of reaching American markets earlier than imported chestnuts, with better quality control, and without the costs of international shipping. However, the key to success in moving large quantities of chestnuts is through marketing, education of the consumer and distributors, and the development of relationships with knowledgeable persons in food-distribution services. Many opportunities for marketing that did not exist in the past for small growers are now available through the Internet, but targeted marketing efforts to the food industry can also be very valuable.Chestnut Species and HybridsFour species of chestnuts and several of their hybrids are grown in the United States today. American chestnuts (Castanea dentata) have small, sweet nuts, upright growth form, and are highly susceptible to chestnut blight. The European chestnut (Catanea sativa) is also blight susceptible and can only be grown in blight-free areas. European chestnuts trees have an upright tree form, and the nuts from European chestnuts can be quite good from some cultivars. However, many of the cultivars and seedlings produce nuts that are bland or bitter in taste and difficult to peel. Chinese chestnuts (Castanea mollissima) are highly blight resistant, and some cultivars produce nuts of good size and sweet taste that are also easy to peel. Chinese chestnut trees are sometimes upright in growth form, but many are low, spreading and multiple branched at the ground. Japanese chestnuts (Castanea crenata) are small, spreading, blight-resistant trees that produce large, poor tasting nuts. Japanese chestnuts are mostly used for hybridization. Chinkapins (several species) produce small, sweet nuts (one per burr), are often of shrubby form and are not used for commercial nut production. The members of the genus Castanea are very closely related and interhybridize readily. Hybrids offer some of the best potential for promising commercial cultivars. In Europe, most chestnut breeding has been done with Japanese x European crosses. In Japan and Korea, the majority of the commercial production today is with Chinese x Japanese hybrid cultivars.In the United States, some of the recently developed American x Chinese hybrids offer the combination of characteristics that make for excellent commercial cultivars for Florida (Fig 1).Figure 1. American x Chinese hybrid chestnut tree.Click thumbnail to enlarge. Nut Quality and GradesSizeA primary concern in any cultivar is the size of the nuts produced. For marketing to a fresh or pre-packaged market, large size is required (Fig 2). While the U.S. Department of Agriculture (USDA) has not adopted any standards for grades of chestnuts, the following size standards were proposed by the USDA in 2001 (Table 1).Figure 2. Customers prefer larger individual nuts.Click thumbnail to enlarge. Importers have sometimes used size standards based on the number of nuts per pound (Table 2). Nuts smaller than 40 count per pound are difficult to distribute through mass marketing systems (brokers and grocery chains) because of the American desire for larger chestnut sizes (Fig 3). Smaller chestnuts are generally less desirable in the American market and bring a lower price. If, however, the chestnuts are used for drying, pureeing, flour or candies, size is not as important.Figure 3. Various nut sizes among chestnut cultivars.Click thumbnail to enlarge. TasteTaste is also very important. Some cultivars have a higher sugar content, even raw. The carbohydrates in chestnuts turn to sugar as the nuts mature and dry. Curing is important before cooking chestnuts, to bring out the flavor of the nuts. The American chestnut is quite sweet, as are chinkapins. Some of the Chinese chestnuts and the American hybrids have very sweet nuts. Some of the European and Chinese varieties are, by comparison, not as sweet.Ease of PeelingThe third nut characteristic of importance is ease of peeling the nut. The pellicle or “skin” that surrounds the kernel is bitter and must be removed before eating. In some types of chestnuts, the pellicle is ingrown into the rough surface of the kernel, which makes the nuts difficult to peel and, therefore, poor eating quality. Many European chestnuts have this undesirable characteristic. The French distinguish between types of chestnuts based on the ease of peeling. Marrons, a chestnut native to the Mediterranean, have smooth-surfaced kernels that are easy to peel, and the chtaignes having an ingrown pellicle. The marrons command a much higher price in the stores in France and in the United States than do the chtaignes, but both types of chestnut are shipped to the United States where they are popular among American consumers. The American and Chinese chestnuts and their hybrids more frequently have smooth kernels and are easier to peel. Ease of peeling is important in commercial processing, as well as for acceptance by the consumer; a little bit of the kernel is lost in the peeling process, and chestnuts that are easily peeled require much less time and expense to remove the pellicles.PropagationThe predominant type of chestnut trees sold in the United States today is Chinese chestnut seedlings. Seedling Chinese chestnuts are generally variable in nut size, taste, tree form and productivity. The trees bear in 3-8 years, much later than grafted stock. The trees are, in some cases, more vigorous than grafted trees and more cold hardy. Most existing plantings of chestnuts in the United States are seedlings. Wide variability in the quality of the crop reduces the marketability of chestnuts.Grafting and budding are the most common ways of propagation for clones of chestnuts. Chestnuts can sometimes be affected by root stock/scion incompatibility. Factors causing this incompatibility are both ecological and genetic. Scions grafted onto rootstock with differing isoenzymes may show poor vigor, inconsistent crops, and sometimes death of the scion above the graft. Grafts fail more in very cold climates or after severe heat or drought stress. Location and SiteChestnuts can be grown in a wide variety of climates and environments, but the range that is suitable for growing peaches is often considered to be suitable for growing many of the chestnut cultivars. Chestnuts also grow well throughout the areas in Florida used for pecan production. The best conditions for the production of nuts include a warm and relatively long growing season and a mild winter. Irrigation is recommended for maximum nut production and is especially important in initial orchard establishment. Though chestnuts flower late, spring frosts can damage new growing shoots, and low-lying frost pockets should be avoided.Chestnuts prefer a well drained, upland sandy loam of pH 5.0-6.5. The soil should not be subject to standing water and/or periodic flooding. If mechanical harvesters are to be used, too much slope in the field can create difficulties in using the machinery, and wet soil conditions with autumn rains can inhibit easy movement through the orchard. North Florida is especially suited to growing chestnuts. Areas from Orlando north through the Florida Panhandle include chestnut plantings that have been growing for more than 40 years.Orchard Planting and ProductionOrchard spacing varies greatly depending upon the cultivar. However, 20X20 (108 trees/acre) is common. This spacing creates the optimum balance between close packing of the trees to increase early production of the orchard and the need to thin trees as the crowns start to touch. Chestnuts require a
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