Determinants of ruminant nutritional quality of pearl millet [Pennisetum glaucum (L.) R. Br.] stover: I. Effects of management alternatives on stover quality and productivity

The paper investigates management and cultivar type effects on pearl millet stover yield and fodder quality. Sixteen pearl millet cultivars available to farmers in India were selected to represent three cultivar types: (1) traditional landrace germplasm from the arid/semi-arid millet production zones, (2) improved dual-purpose (grain and stover) open-pollinated varieties incorporating differing amounts of traditional landrace germplasm and (3) commercial, grain-type F1 hybrids, bred for use in the arid/semi-arid zone. The cultivars were grown for 2 years (2000 and 2001) at high fertility (HF: 65 kg N ha⁻¹ and 18 kg P ha⁻¹) and low fertility (LF: 21 kg N ha⁻¹ and 9 kg P ha⁻¹). Within each fertility level high (HP) and low (LP) plant population densities were established by varying sowing rate and then thinning to the target populations (HP: 11 plants m⁻² and LP: 5 plants m⁻²). Stover fodder quality traits (nitrogen concentration, sugar content, in vitro digestibility and metabolizable energy content) were analyzed using a combination of conventional laboratory analysis and near infrared spectroscopy. In general, fertility level and cultivar type had strong effects on grain and stover yields, and on a range of stover nutritional quality traits, but with significant year interactions. In contrast, the effect of population density on these variables was largely insignificant. Higher fertilizer application significantly increased grain and stover yields and stover nitrogen concentration, in vitro digestibility and metabolizable energy content. As a result, fertilization resulted in significant increases in the yields of both digestible and metabolizable stover. Landrace cultivars as a group produced higher quality fodder than modern hybrids, but at a significant cost in grain yield. Dual-purpose, open-pollinated cultivars were generally intermediate between the landraces and hybrids, in terms of both stover quality and grain yield, but produced the highest yields of both digestible and metabolizable stover. The paper discusses the implications of these findings for Indian pearl millet farmers with various resource levels and farming objectives.     

大豆不同品种类型对播期及密度的反应

选取结荚习性、分枝性不同的四个品种为试材,采用二因素最优化设计,进行了品种、播期、密度的综合试验,并建立了数学模型。 结果表明:各类型品种在同一地区种植均可获得高产,但需配有相应的最佳栽培模式;播期与密度对产量影响均较大。播期早晚主要影响花前期长短,进而影响产量。无限型品种适宜的密度较低且范围较窄;分枝性强的有限型品种,适宜密度较高,范围较宽;独秆型品种则要求密度高,范围最窄。产量与单位面积总荚数相关最为密切(r=0.934),每平方米总荚数高于700,可获得每亩高于150公斤的产量。     

冬小麦小量播种的品种和播量筛选及产量和品质效应研究

为了筛选一批适于小量播种的品种．并确定其适宜播量，2001—2003年，以13个品种为材料进行了小量播种试验。试验结果表明，在参试品种中，DS1号、临抗1号、冀麦30、鲁麦21和京411适于小量播种。适宜播种量为22．5kg／hm^2。试验中，这些品种生长发育正常，有较强的单株分蘖能力，主茎和大分蘖的穗分化能同步完成，均具有较高的单株穗数。在22．5kg／hm^2播量条件下，5个品种的产量为6652．5～8537．7kg／hm^2。在2002—2003试验年度中，京411、鲁麦21、临抗1号、DS1号的最高产量分别达到10005．0、8704．35、7553．85、7503．75kg／hm^2。在高产的基础上，一些品质性状表现也较好。     

聚丙烯酰胺凝胶电泳（PAGE）在烤烟品种鉴别中的应用

随着烤烟品种数目的增多，单从形态上鉴别比较困难。本文报道了应用PAGE鉴别8个烤烟品种的试验结果。种子酸溶蛋白质、盐溶蛋白质SD8—PAGE无法将各品种区分开来；幼苗酯酶同工酶PAGE则能很好地鉴别出这8个品种，显示出其在烤烟品种鉴别中的潜力。     

4种体色柞蚕品种遗传关系的RAPD分析

利用随机扩增多态DNA(RAPD)标记技术,对分别属于4种体色系统的13个柞蚕品种进行了基因组DNA多态性分析。利用筛选出的33个随机引物扩增出265条DNA带,其中多态性带227条,占85.66%。根据扩增结果计算品种间的单匹配相似系数,用Ne ighbor-Join ing法构建了聚类树状图。4种体色13个品种并没有按所属体色系统聚在一起,即品种的遗传聚类划分与体色之间的相关性不大,表明柞蚕体色并不能真实反映品种间的遗传关系。     

桃品种耐寒性研究

用电导法、萌芽生长法和组织变褐法对82个桃品种或优系的耐寒性评价,结果表明：桃一年生休眠枝的耐寒温度为-19．0～-27．0℃,叶芽为-18．5～-26．1℃,花芽为-17．0～-24．0℃;枝、叶芽和花芽三者间耐寒性呈显著正相关,抗性强弱的顺序为：枝＞叶芽＞花芽;枝组织的耐寒力顺序为：韧皮部＞木质部＞形成层＞髓;品种间、品种群间及变种间抗寒性也有不同程度的差异。提出在很少发生-23．0℃以下低温的地区为桃适宜经济栽培区。     

樱花新品种‘锦绣’特征习性及园林应用

华中樱桃Cerasus conradinae是广泛分布于我国的特有樱属植物，是樱花种质创新的优异资源，具有非常高的开发利用价值。‘锦绣’是从湖北省赤壁市官塘驿镇的野生华中樱桃群落中的一变异单株选育而来。2016年1月和2017年1月分别进行第一代和第二代嫁接。通过观察对比，嫁接苗性状表现一致、稳定。2021年6月获得新品种授权（植物新品种权号：20210197）。该品种叶片边缘波皱明显，具显著腺体，常分泌粘液；伞房花序，5～12朵，花单瓣，5枚，淡紫粉色，平盘形，花期3月中下旬。该品种树形高大、生长迅速、花量繁密、花有芳香、适应性广，值得大力推广应用。     

不同种植密度对玉米品种产量形成及生长发育特性的影响

以先玉335、京科968、迪卡159和赤单228为供试材料，采用随机区组设计，设有高中低3个密度处理，研究其对4个玉米品种产量及其生长发育特性的影响。结果表明：随着种植密度的增加，4个玉米品种穗长、穗粒数和千粒重均呈逐渐减少的规律性变化，这表明种植密度的增加影响玉米果穗的形成和灌浆。玉米不同品种果穗生长情况均是前期较慢，后期呈现指数增长，增长迅速。从产量结果看：赤单228最佳种植密度为8.25株·hm^-2，迪卡159在种植密度是8.25株·hm^-2。而京科968和先玉335产量在7.50株·hm^-2时，产量达到最大。     

Bruise susceptibility of banana peel in relation to genotype and post-climacteric storage conditions

The aim of this study was to understand the genotypic factors and post-climacteric storage conditions that affect bruise susceptibility of banana peel. Putative physicochemical indicators of bruise susceptibility, including peel electrolyte leakage (PEL), total polyphenolic content, hardness, water content, and peel thickness, were investigated. Bruise susceptibility is the lowest impact energy needed to produce visible bruising by an object dropped on post-climacteric banana fruit from a pre-determined height, converted into impact energy (20–200 mJ with a 20 mJ increment). The bananas were stored either at 18 °C throughout ripening or at 13 °C between the 2nd and 6th day after ethylene induction. Five cultivars with contrasting susceptibility to impact bruises were used. Neither Grande Naine nor hybrid Flhorban925 bruised at the maximum impact energy (200 mJ) during ripening whatever the storage conditions. A gradient in bruise susceptibility was observed among the other cultivars: French Corne > Fougamou > hybrid Flhorban916. Bruise susceptibility increased during ripening and was higher in bananas stored at 18 °C. The lower ripening temperature resulted in a two-day delay to fruit maturity as well as in bruise susceptibility. Bruise susceptibility was positively correlated with PEL (R = 0.78) and to a lesser extent negatively correlated with hardness (R = −0.45), and was not correlated with polyphenolic content. In conclusion, membrane permeability provides the first clue to understanding bruise susceptibility.     

Microstructural characterisation of commercial kiwifruit cultivars using X-ray micro computed tomography

The skin is the physical barrier between the fruit and the environment in which it develops. Environmental conditions during fruit development have a large influence on fruit quality, both at the time of harvest and during subsequent storage. It is hypothesised that some features of the skin and sub-epidermal tissues could provide information about the past growing conditions to which the fruit was exposed and therefore be of predictive value for storage quality. In this study, five commercial kiwifruit cultivars (‘Hayward’, ‘Hort16A’, ‘G3’, ‘G9’ and ‘G14’) were studied, and ‘Hayward’ fruit were manipulated during growth with different cultural practices. After harvest at horticultural maturity, X-ray micro computed tomography (μCT) was used to investigate features of the skin and the immediate parenchyma tissue. Despite orchard management practices (crop load and girdling) being observed to effect macro fruit quality parameters (mass, firmness, SSC, and DM), differences in microstructure (e.g. porosity) caused by these practices were not observed. However, porosity and pore size were found to be highly variable between cultivars. The thickness of dense sub-epidermal tissue could be readily measured and the 3-D distribution of raphide bundles was visible as high density particles distributed within the parenchyma. Overall, μCT was found to be a powerful technique to explore fruit epidermal and sub-epidermal structures in three dimensions at a micro level. However, the length of time required for data capture and analysis and the large number of samples required to overcome natural variation within horticultural products need to be considered. Future work may define the impact of differences in porosity or sub-epidermal anatomy on kiwifruit physiology (e.g. firmness change or sensitivity to low oxygen storage atmospheres). With this information, μCT could be used as a screening tool during plant breeding, or to determine the response to agronomic treatments, without conducting lengthy storage trials.