Seed Yield Stability of Okra as Influenced by Planting Date

Fifteen selected okra varieties consisting of ten newly-developed lines and five established varieties were evaluated for stability of seed yields in eight different environments i.e. several monthly plantings for three consecutive years. Seed yield data were analyzed to determine the effectiveness of using different planting dates in seed yield trials of new okra varieties. The wide ranges of environmental indices (- 10.8 to 24.4) and seed yield (2.7 to 38.0 g plant ^-1) indicated significant variation between the environments even though the trials were conducted at the same location. A regression method of stability analysis showed that the mean differences between environments, the varieties and their interactions were highly significant. These results suggest that where limited resources prevent the use of several locations, different dates of planting for two or more years could be used to evaluate okra varieties for seed yield without losing much information on their relative ranking.     

加工专用型紫色甘薯品种的筛选与鉴定

为筛选适宜连城县种植的加工专用型紫色甘薯新品种,采取随机区组设计,以‘龙岩7-3’为对照,2012年秋季引进5个紫色甘薯新品种进行品种比较试验,从农艺性状、经济性状、薯块的营养品质、甘薯干和油炸脆片产品的加工品质等方面进行筛选鉴定。结果表明：各品种表现不同。其中,‘伟祥1号’鲜薯产量最高达41.9 t/hm²,比对照‘龙岩7-3’增产25.8%。‘济薯18号’鲜薯产量为31.6 t/hm²,与‘龙岩7-3’相当。‘济薯18’和‘伟祥1号’加工的甘薯干,不仅在工艺稳定性、口感、色变等综合指标,均接近‘龙岩7- 3’,而且在产品的形态、色泽、透明度、口感和质地等方面均表现优异,可作为加工甘薯干的紫薯品种。‘济薯18’和‘伟祥1号’加工的油炸薯片,含油率适中,膨化度高,产品品质与对照‘龙岩7-3’相当,可作为加工油炸薯片的紫薯品种。‘福薯9号’、‘泉紫薯1号’和‘宁紫薯1号’的薯形美观,营养品质高,食味粉香,适合优质鲜食和加工甘薯全粉用。     

Genotypic Variability in Adaptation Responses of Selected Clones of Cassava to Drought Stress in the Sudan Savanna Zone of Nigeria

Identification of drought‐tolerant and ‐resistant varieties of cassava is of paramount importance for the maximization of productivity potential in drought‐prone areas. Nine improved cassava varieties developed in humid and subhumid agro‐ecologies were evaluated for their growth responses and adaptability in the dry savannas of Nigeria. Field trials were set up in two cropping seasons at three different locations. Parameters evaluated included fresh root yield (FRY), fresh shoot yield (FSY), cumulative leaves formed (CLF), cumulative leaf scars (CLS), root dry‐matter content (DMC), harvest index (HI), and root cyanogenic potential (CNp). Results demonstrated that varietal response differed with water table site, implying different adaptation responses of varieties to the water regime. Variations in all characters studied were significantly (P<0.05) influenced by genotype, suggesting a strong genetic basis for the phenotypic differences amongst varieties. Compared with variation attributable to location, the genotypic components were strong for FRY, FSY, CLF, CLS, HI and DMC. HI and DMC were not significantly affected by location. CNp tended to increase with increasing drought stress. The significance of genotype × environment effects for FRY suggested that genotypes may be selected for specific adaptation for drought‐prone environments. The poor adaptability responses of the majority of the varieties implied that an agro‐ecologically targeted breeding scheme for the dry savanna would be a more appropriate approach for the development of drought‐tolerant varieties.     

Effects of farmers' seed management on performance and adaptation of pearl millet in Rajasthan, India

Pearl millet (Pennisetum glaucum [L.]R.Br.) is the staple food and fodder crop of farmers in the semi-arid areas of north-west India. The majority of farmer sin western Rajasthan depend on their own seed production and employ different seed production strategies that involve different levels of modern-variety introgression into landraces as well as different selection methods. This study quantifies the effects of three seed management strategies on environmental adaptation and trait performance. Forty-eight entries representing farmers’ grain stocks — pure landraces or landraces with introgressed germ plasm from modern varieties — as well as 33 modern varieties, multiplied by breeders or farmers, were evaluated in field trials at three different locations over two years under varying drought-stress conditions. Results indicate that the plant characteristics employed by farmers in describing adaptive value and productivity is an effective approach in discriminating the type of millet adapted to stress and non-stress conditions. It was also found that introgression of modern varieties(MVs) leads to populations with a broader adaptation ability in comparison to pure landraces or MVs alone – but only if MV introgression is practised regularly and is combined with mass panicle selection. Under high-rainfall conditions, farmer grain stocks with MV introgression show similar productivity levels as modern varieties. Under lessening rainfall, pure landraces show, in tendency, higher grain yields. In conclusion, farmers’ seed management could form an integral part of participatory breeding programs. This revised version was published online in July 2006 with corrections to the Cover Date.     

云南黄心甘薯地方品种特性分析

１９９６～１９９７年对征集到的２４份云南黄心甘薯地方品种资源进行了农艺性状、生长特性、抗逆性、生产力及营养品质的分析、评价，结果表明：蒙自黄心、红鸡窝、普洱黄山芋、紫红皮、甘心红薯、路南红皮、东川白花等一批黄心地方品种生长势强、适应性强、块根产量高、品质优，开发利用潜力较大。     

3种专用型甘薯光合光响应曲线及其模型拟合

为了揭示甘薯光合光响应特性,并为其筛选出最佳的光合响应曲线拟合模型,准确求得光合主要参数,运用直角双曲线模型、非直角双曲线模型、指数函数模型以及直角双曲线修正模型的方法分别对3种专用型甘薯（鲜食型甘薯、淀粉型甘薯和花青素型甘薯）叶片的光合光响应曲线进行拟合。直角双曲线模型拟合的最大净光合速率(Pnmax)和暗呼吸速率(Rd)远大与实测值,光饱和点(Isat)小于实测值,非直角双曲线模型拟合的Pnmax大于实测值,Isat则远小于实测值,而指数函数模型拟合的Isat、Rd和光补偿点(Ic)均远小于实测值;只有经直角双曲线修正模型拟合所得的光合参数值最接近实测值,且能拟合甘薯光合光响应曲线的光抑制部分。通过比较3种类型甘薯光合特性可知,鲜食型甘薯和淀粉型甘薯的Pnmax和Isat均高于花青素型甘薯,但各类型甘薯的Ic和Rd无明显差异。直角双曲线修正模型所求得光合参数值最接近实测值,日后可运用该模型准确、高效地研究甘薯光合特性;鲜食型甘薯和淀粉型甘薯具有更大的光强适应范围和光合产物的积累潜力。     

海拔差异对紫色甘薯品种的影响

通过对引进的‘11-07’、‘16-08’、‘Y1’和‘SCZ’ 4个紫色甘薯品种分别在云南省玉溪市3个不同海拔的山地种植,分析其生物学特性、丰产性、品质等指标。结果表明：在海拔2000 m以上,以‘11-07’和‘SCZ’的产量较高,在海拔1600 m~1700 m左右,以‘SCZ’的产量最高。综合4个品种的产量和品质,‘SCZ’可作为有价值的商品紫薯品种引到玉溪的山地推广种植,‘11-07’可作为替补品种,为玉溪市不同海拔山地选择种植优良紫色甘薯品种提供科学依据。     

广西高淀粉甘薯引种试验初报

为了选育出适合广西栽培的高淀粉含量能源型甘薯新品种,对9个引进的品种进行对比试验,通过采用随机区组设计,以‘广薯87’为对照,研究不同品种的植株地上部性状、块根性状、鲜薯产量和淀粉含量等。结果表明,JSP-4和‘徐薯22’的淀粉产量较高,分别达到6698.42 kg/hm2和5685.96 kg/hm2,分别比对照高43.54%和21.84%。通过研究得出,JSP-4和‘徐薯22’可作为高淀粉含量的能源型甘薯品种在广西推广种植。     

Comparison of stability statistics for yield and quality traits in bread wheat

The stability and genotypic mean of four traits, grain yield, grain protein content, alveograph W and bread volume, were evaluated in three multi-location trials, each covering two years. The stability of each genotype was evaluated by environmental variance (s² _E), interaction variance (s² _W) and variance of the ranks of the phenotypic values corrected for the genotypic effect (s² _R). The bootstrap method was used to study correlations between the genotypic mean and the three stability statistics and to calculate their accuracy. The repeatability of the stability statistics was measured by correlations between the values obtained in each of the two years. In addition, theoretical smaller trials were generated by random sampling and the stability values calculated were correlated with those of the original trial. Environmental variance appears to be usable both for yield and for quality traits, but there is a risk of counter-selecting a high genotypic mean of W. Whatever the trait and statistic envisaged, stability is poorly repeatable and its evaluation requires several years and a large number of locations per year to minimise sampling and environmental effects. This revised version was published online in August 2006 with corrections to the Cover Date.     

紫色甘薯新品种引进鉴定及利用

为筛选适宜龙岩市种植的紫色甘薯新品种,采取一年多点完全随机区组试验设计,以“金山57”为对照,2014年夏季引进6个紫色甘薯新品种进行品种比较试验,从农艺性状、经济性状、鲜产、干产、淀粉产量、品质和花青素含量等方面进行筛选鉴定。结果表明：6个紫色甘薯新品种中,2个品种表现较好。其中,‘龙津薯1号’鲜薯产量最高,为39.11t/hm2,薯干产量9.22 t/hm2,淀粉产量5.53 t/hm2,干物率23.57%,淀粉率14.15%,食味评分80.0分,花青素含量17.66mg/100g。‘福薯24号’鲜薯产量其次,为36.30 t/hm2,薯干产量10.82 t/hm2,比对照增产3.32%,淀粉产量7.11 t/hm2,比对照增产6.77%。干物率29.81%,淀粉率19.57%,食味评分84.7分,花青素含量11.95mg/100g。‘龙津薯1号’鲜薯产量高,干物率和花青素含量指标适宜,可以推荐作为紫色地瓜干加工品种在龙岩市推广种植。‘福薯24号’鲜薯产量较高,食味品质好,干物率和淀粉产量高,可以推荐作为鲜食型和紫色淀粉加工型品种在龙岩市推广。‘广紫薯8号’将进一步观测。‘福宁紫3号’、‘宁紫薯1号’和‘徐紫薯2号’等品种均不适宜在龙岩市推广种植。     

宁夏南部冷凉地区紫薯新品种引进高产栽培比较试验研究

紫薯市场的需求量与日俱增,应对市场对紫薯品质,产量的要求,筛选适合原州区种植的高产的优良紫薯品种是当前的主要任务。通过从9个品种的产量和基本成分分析得出,徐紫薯1号产量最高,淀粉含量达到最高56.47%,口感好。广紫薯135号薯形较美观,薯块紫红皮,紫花色肉,耐贮性好,萌芽性好,适口性好,属优质品种。宁紫4号产量较高、适应性强,蛋白质含量4.72%,淀粉含量47.58%,总糖4.57%,粗纤维2.95%。而且均具有抗旱、耐瘠薄等特点,薯块均匀、薯皮光滑、鲜食口感很好,色泽鲜艳、肉质细腻,最适宜薯产区种植。     

Stability of performance of tetraploid wheat landraces in the Ethiopian highland

Plant breeding has always been concerned with genotype-environment interaction. Normally high and stable performance are desirable attributes of cultivars. However, this is practically difficult to achieve where environmental variations are high and unpredictable and significant genotype-environment interactions occur. Stability of performance of 13 landraces evaluated at 4 different locations for 3 years in the highlands of Ethiopia was investigated. The testing locations have different climatic and edaphic conditions providing the conditions necessary for the assessment of stability. Stability parameters like b, s²d, s², r² and cv which are in common use were employed. Grain yield and 1000-kernel weight were the agronomic traits considered for the stability analysis. There were differences in the ranks of genotypes across the locations. Significant main environmental as well as interaction effects were observed showing the importance of genotype-environment interaction in both traits. Many of the landraces evaluated are rated as stable for these traits within the environmental conditions prevailing in these highland locations. Genotypes with specific adaptation to poor and favourable conditions were also identified. Certain genotypes showed similar manners of adaptation and stability for both of the traits. Grain yield showed low correlations with the stability parameters showing the possibility of attaining high yield and stability. Correlations between the stability parameters were mainly positive and significant for grain yield. Only a few of these correlations were found to be significant for kernel weight. The good adaptability of landraces should be exploited in the improvement of their yield potential. This revised version was published online in July 2006 with corrections to the Cover Date.     

脆片加工型紫色甘薯筛选品种比较试验

为了筛选出适合脆片加工使用的紫薯品种,以‘山川紫’为对照,2011年引进8个紫薯品种进行比较试验,从经济性状、生物学特性以及蒸食品质等方面进行筛选鉴定。结果表明：各品种表现不一,其中‘京紫6号’、‘桂紫12号’综合表现较好,鲜薯产量分别达到30214.5 kg/hm2和28042.5 kg/hm2,分别比对照高58.2%和46.8%;商品薯率较高,分别为88.2%和86.3%;薯块大小中等且整齐度好;口感软香甜粉,粗纤维量少,食用品质优良。这2个品种为初步筛选出的在经济性状、生物学品质以及蒸食品质方面符合脆片加工使用的品种。     

不同类型甘薯茎和叶中碳、氮、磷化学计量学特征研究

选取3个鲜食型、3个淀粉型和3个紫甘薯品种,于不同生育期采集地上部茎、叶样品,测定其碳（C）、氮（N）、磷（P）含量,研究不同类型甘薯C、N、P生态化学计量学特征及其随生育期的变化规律。结果表明,甘薯叶中C、N、P含量范围分别为391~399、26.3~29.1、2.90~3.10mg/g,茎中分别为421~428、11.6~15.2、4.99~5.77mg/g,其在茎、叶中的差异大于甘薯类型间的差异;茎中C含量随生育期延长略有增加,但茎、叶中N和P含量则随生育期延长而降低,茎、叶中C、N、P含量随生育时期的变化大于甘薯类型间的变化。不同类型甘薯叶中C/N、C/P分别以紫甘薯和淀粉型甘薯最大,说明紫甘薯和淀粉型甘薯有较高的碳同化能力;3种类型甘薯叶中N/P为8.57~9.97,表明N元素是甘薯茎叶生长的主要限制因子。     

甘薯实生系与其无性系性状相关关系及早期选择利用研究

甘暮实生系是分离世代,其性状的变异与资源品种表现同一趋势,与其无性系在诸多性状上呈强弱不同的正相关关系,这是对实生系进行早期选择利用的基础.根据结薯性可将实生系分为成薯、膨大和直根3个类型,成薯系%因组合而异,受环境影响不明显.5年的研究结果证明:无性系类型间的产量性状有明显差异,从成薯类型选育高产新品系的入选率高.在此问题上和美国Granberry.M.等的认识不同.建议把我国甘薯育种的初选期提早到实生系时期,以缩短育种周期,提高育种效率.笔者认为把甘薯杂交种子培育的株系,定名为实生系,比较确切.     

甘薯不同品种田间产量与淀粉糊化特性的比较研究

为了系统比较研究不同品种甘薯的产量、干率、淀粉含量及淀粉糊特性之间的差异和相关性。采用大田试验,测定了中国近年来31个甘薯主栽品种的产量、干率和淀粉含量,并利用快速粘度分析仪(RVA)测定了这些甘薯品种淀粉的糊化特性。结果表明,供试各品种间以‘南薯88’单株薯重最高,达到1.56 kg/株;品种间干率和淀粉率也存在一定差异,变幅分别为20.57%~40.87%和11.54%~29.13%;鲜薯产量以‘南薯88’最高,达到78065.61 kg/hm²,其次是‘泰中10号’,为63325.17 kg/hm²,各品种间差异极显著。不同品种的RVA谱差异明显,主要表现在各个黏滞性特征值上,其中最终粘度和回复值的品种间差异较大。峰值粘度与终值黏度、峰值黏度与回复值、谷值黏度与终值黏度、谷值黏度与回复值、终值黏度与回复值间均存在显著正相关,糊化温度与各特征值（除峰值时间）存在负相关。     

甘薯种质资源盆栽保存基质的筛选与评价

为了筛选和优化盆栽基质配比,用于国家种质广州甘薯圃内甘薯资源的盆栽保存,本研究以田土、沙和泥炭土为材料,进行7种基质配比,并利用不同资源品种生长指标测定值对其进行评价与筛选。利用隶属函数、变异系数及主成分分析法对不同基质条件下,不同资源品种地上部鲜重、薯块产量等生长指标进行分析。结果显示：基质5(50%壤土+20%沙+30%泥炭土)条件下,不同甘薯资源品种生长指标变异系数综合隶属函数值及主成分综合评价值最高,分别为8.1639和0.8725,表明基质5可更大程度上保证甘薯资源品种的活力,体现资源品种的种性特征。综上所述,基质5可作为甘薯种质资源盆栽保存的优良基质。     

Specific and General Adaptation and Yield Stability of Wheat (Triticum aestivum L.) Genotypes

Mean grain yield performance of 12 wheat and one triticale genotypes were measured at four locations over four consecutive years, using a randomized complete block design with four replications. The genotypes used were commercial cultivars and advanced lines from different wheat breeding projects located in different areas in Iran. Two locations were in semiarid regions and the other two locations in the temperate zones. The combined analysis of variance indicated highly significant genotype-environment (GE) interactions. From combinations of locations and years three sets of environments were generated. Set I and set II, each, consisted of eight environments (two locations and four years) representing semiarid and temperature environments, respectively. Set III consisted of 16 environments including both semiarid and temperate conditions. Set I and set II were used to measure specific adaptation of the genotypes while set III was employed for measuring general adaptation. The methods of Eberhart and Russell (1966) were used for partitioning GE interactions. The mean square associated with the heterogeneity of regression was highly significant under all sets of environments. These observations indicated that a major part of GE interaction could be accounted for by differences in the regression of the individual genotypes. All the genotypes had significant regression mean square under set I, set II, and set III environments, with the exception of two genotypes under set II. However, mean yields, regression coefficients, and the mean squares associated with deviation from regression greatly varied over the sets of environments. Only three genotypes, a commercial cultivar and two new advanced line, were identified as having specific adaptation and yield stability to semiarid environments. Among all the genotypes, only a commercial cultivar was identified as adapted and stable to temperate conditions. Two of the three genotypes which were adapted to semiarid environments also showed general adaptation to set III environments. However, the mean yield of these two genotypes under semiarid conditions (set I) were significantly greater than their respective mean yields under set III environments. Thus, wider adaptability was compensated by lower mean yield. The present study indicates that, while a wide range of environments is necessary and recommended for measuring general adaptation reactions and yield stability of various genotypes, one should not ignore the possibility of finding some genotypes with specific adaptation to specific environments and thus maximizing yield production. Stable genotypes with general of specific adaptation should be utilized in breeding projects in order to develop even more desirable lines.     

Plant traits related to yield of wheat in early, late, or continuous drought conditions

Bread wheats (Triticum aestivum L.) were evaluated for plant characteristics contributing to grain yield and plant adaptation under various drought patterns. The usefulness of these traits as explicit selection criteria in developing drought tolerant wheat varieties was investigated in three experiments. Cultivars from four germplasm groups, representing the four relevant major and distinct global wheat growing environments, were grown under the respective simulated early, late, continuous and no drought conditions by manipulating irrigation in north western Mexico. Additionally, 560 advanced lines from the CIMMYT breeding program were grown under late drought conditions, and 16 randomly selected advanced genotypes were studied in more detail under late and no drought conditions. In these three studies, the association between yield in drought-stressed environments and yield in non drought-stressed environments was interpreted to reflect genotypic high yield potential, mainly by way of high biomass development. However, yield potential only partly explained the superior performance under drought. For each pattern of drought stress, particular and often different plant traits were identified that further contributed specific adaptation to the distinct drought stress conditions. Knowledge of these traits will be useful for developing CIMMYT germplasm for specific drought-stressed areas. Ultimately, these studies demonstrate that both yield potential and specific adaptation traits are useful criteria in breeding for drought environments, and should be combined to achieve optimum performance and adaptation to drought stress. This revised version was published online in August 2006 with corrections to the Cover Date.