Heritability of, and genetic correlations among, forage and seed yield traits in Ladino white clover

Sixteen white clover genotypes and their half-sib progenies were grown in pure stand. Each clover progeny was also grown in a mixed stand that also included three grass varieties of different species. Dry matter (DM) yield was measured over 2 years and seed yield at the second year. Competitive ability of clover families was defined as the ratio between mixed stand and pure stand for clover DM yield. Narrow-sense heritability from parent-offspring regression of pure stand data was high to moderate (h²0.50) for DM yield, seed yield and most of their components. Persistence as predicted by stolon density showed negative genetic correlations with seed yield (r_g= -0.70) and DM yield (r₂= -0.60), whereas seed yield and DM yield tended towards a negative correlation (r₂=0.45). Sizes of different vegetative or reproductive organs were generally correlated positively. Evidence was provided that the set of parent genotypes represents well the genetic variation available within the Ladino gene pool. The results highlighted the difficulty of combining relatively short-term DM yield, persistence and seed yield into a unique plant type. Differences in competitive ability emerged only in the second year, better ability being related mainly to petiole length among the traits assessed in pure stand.     

Differentiation in competitive ability and cold tolerance between diploid and tetraploid cultivars in Lolium perenne

In a diploid grass, perennial ryegrass (Lolium perenne L.), many autotetraploid cultivars have been released and widely used in many cool temperate countries. In this study, competitive ability and cold tolerance, which seem to be important factors in determining geographical distribution and persistency of this species, were compared between six diploid and five autotetraploid cultivars. The tetraploid cultivars had significantly higher competitive ability and lower cold tolerance than the diploid cultivars. Furthermore, there was no overlap in the two traits between them. These results suggest that chromosome doubling has a larger effect on competitive ability and cold tolerance than does the genetic difference between the populations within a single ploidy level. This revised version was published online in August 2006 with corrections to the Cover Date.     

土壤水分对冬小麦初生根和次生根生长发育的影响

１９９３－１９９４年冬小麦管栽水分试验结果表明,初生根与次生根生长量、数量及分枝能力基本与土体水量呈正相关,胁迫程度愈深,受抑程度愈大。初生根特别是一、二次根及其分枝数人有很强抗逆能力。水量愈大,三,四次根数愈多。次生根尤其是其数量对对水土土水环境极为敏感。当土壤含水量低于田间持水量６０％时,受到严重抑制。胁迫后复水,使初一根三次根数量增加,根系活性延长,地次生根的激励作用更大,前期胁迫愈严重。促     

冬小麦亲本配合力在不同世代和年份间的稳定性研究

用９个冬小麦亲本按ＮＣＩＩ交配设计配成２０个杂交组合,分析了Ｆ２－Ｆ５世代８个产量性状的配合力在世代和年份间的稳定性。结果表明：克草粒数（籽粒数／茎秆草重）、千粒篝,收获指数、每穗粒重和每穗粒数的一般配合力在不同世代和年份间表现基本一致,早代测定的可靠性高。单株粒重和生物产量的一般配合力在Ｆ２、Ｆ３世代间相关性低,Ｆ４代以后明显增高,说明宜晚代测定配合力。在Ｆ４、Ｆ５世代间所有性状的特殊配合力均显     

玉米478近缘系的性状分析：Ⅱ.配合力分析

对由７个４７８近缘系组配的３５个杂交组合的１３个数量性状进行了分析。结果表明：１．４７８近缘系之间的一般配合力在多数数量性状上存在着显著的差异;２．在特定的杂交组合内,有些４７８近缘系可以相互替代;３．在不同的杂交组合内,可以相互替代的４７８近缘系不同。     

Petri网理论及其在食品工业中的应用

Ｐｅｔｒｉ网是用于描述和分析异步并发系统的最常用的形式模型之一．本文给出了赋时着色Ｐｅｔｒｉ网和赋时连续Ｐｅｔｒｉ网,通过扩展上述模型,得到具有层次的Ｐｅｔｒｉ网．探讨了层次结构Ｐｅｔｒｉ网在现代食品工业企业中的应用,包括生产线的建模和分析,以及后勤系统的设计．     

特优559产量构成因素及丰产稳产性分析

应用数理统计方法对特优５５９产量构成因素及丰产稳产性进行了分析,结果表明：特优５５９丰产性、稳产性好,适应性强。产量构成因素中以穗数与产量的关系最为密切,对产量的作用最大,其次是每穗总粒数,再次是结实率,千粒重对产量的作用不大。揭示其高产途径和主攻目标是“攻足穗,争大穗,提高结实率,稳定粒重”,使穗、粒、重协调发展,夺取高产。     

云南省蚕豆新品种联合区域试验试点综合评价

根据云南省2019—2020年蚕豆新品种联合区域试验结果,从试点精度、生产水平、有效性、分辨力、稳定性和代表性等6个方面对8个区试试点进行综合评价.结果表明,8个区试试点的精度都比较高,数据有效,试验可靠;8个区试试点的产量分别代表了不同的大田生产水平;弥渡、巍山、湾桥、保山等4个试点具有较高的品种分辨力;弥渡、保山2...     

食物对荔枝蝽生殖和存活的影响

食物显著地影响荔枝蝽的卵巢发育,产卵量和成虫的产卵期寿命,罩养于支树花（果）枝上,荔枝蝽每雌平均产卵２２２．３粒,净增殖率为１１０．５７;雌、雄成虫的平均寿命分别为９６．２５和９３．１９ｄ。罩养于嫩枝上者,每雌平均产卵１９３．４ ,净增殖率为９６．２６;雌、雄成虫的平均寿命分别为８９．６９和８９．２５ｄ。罩养于老枝上的成虫不能产卵,雌,雄成虫的平均寿命分别为７０．４４和７０．３１ｄ。在花（果）枝上