Impact of introducing a herb pasture area into a New Zealand sheep and beef hill country farm system: a modeling analysis

New Zealand is well known for export of meat and dairy products from low cost pastoral systems. These farm systems are continually evolving for increased efficiency, in part through the use of metabolic energy modeling tools by farmers and farm consultants to explore alternative farm system configurations and identify new efficiencies. One recent innovation is the introduction of a herb pasture area, such as plantain. We used metabolic energy modeling to quantify seasonal feed flows in two successive years in a New Zealand hill country farm system, and to analyze the impact of the introduction of an area of plantain. Models employed were a self-built Microsoft Excel spreadsheet and a commercial New Zealand farm systems modeling package, FARMAX. Herbage production, animal performance and financial results for a base farm scenario created from the average of survey data for hill farms in the southern North Island, and the same farm with 10% and 20% of the area in plantain for the years 2010–2011 and 2011–2012 were modeled. The self-built model performed similarly to the commercial model. The system configuration of the base farm stockpiles surplus autumn feed for release to animals in winter and also incorporates flexibility that confers resilience to interannual weather variation through varying dates animals are purchased or sold. The introduction of an area of plantain was predicted to increase herbage production, animal performance and financial returns. The predicted benefit was higher for the year 2010–2011 where a drought occurred in summer than for the following year with higher summer rainfall. This demonstrates the profitability of introducing a plantain area to New Zealand hill farm systems, and suggests plantain will assist to mitigate adverse effects of warmer and drier summer conditions associated with current climate change trends.     

非洲香蕉和大蕉产销概况

非洲是全球重要的香蕉和大蕉产出地。2009年非洲香蕉总产约为世界的12.6%;大蕉总产约为世界的81%。两者合计非洲香蕉和大蕉总产约为世界的28%。尤其在非洲撒哈拉边缘,大蕉占了当地大约1亿居民主食的四分之一。非洲香蕉和大蕉主生产区主要分布在非洲东部、西部和中部。东部非洲各国香蕉总产大约为780万t,平均每公顷香蕉产出仅6.7t;大蕉总产大约为1 400万t;香蕉产量上乌干达、卢旺达,坦桑尼亚,肯尼亚分别为前4名;大蕉产量方面,坦桑尼亚,布隆迪、乌干达、肯尼亚分别为前4名。西部非洲各个国家香蕉总产大约为92万t;大蕉总产大约为840万t;香蕉产量上科特迪瓦、几内亚、利比里亚、加纳分别为前4名;大蕉产量方面加纳、尼日利亚、科特迪瓦、几内亚分别为前4名。中部非洲各个国家香蕉总产大约为170万t;平均每公顷单产约7 t;大蕉总产大约为306万t;香蕉产量中安哥拉、喀麦隆、刚果民主共和国、中非分别为前4名;大蕉产量方面喀麦隆、刚果民主共和国、加蓬、中非分别为前4名。尽管非洲是重要的大蕉和香蕉生产区,但只有香蕉被用于出口,目前非洲香蕉出口地主要集中在欧共体市场,占欧共体市场11%的份额,其出口长期由喀麦隆和象牙塔国家垄断,自2006年后加纳开拓了欧盟市场。     

车前草穗枯病发生规律与综合防治研究

车前草穗枯病（Fusicoccum sp.）是江西省吉安县车前草上一种重要病害,主要为害穗部,也能侵害叶片,发病严重时,病株提前枯死,减产90%以上,甚至颗粒无收。田间系统观察的结果表明,病菌以菌丝体和分生孢子附着病株残体上,遗留在田间土表越夏、越冬,次年3～4月车前草抽穗期,气温15～30℃,病菌的分生孢子借风雨传播,落在车前草的叶片和穗部,温、湿度适宜时,萌发侵入为害,引起发病。越冬菌源多,氮肥施用过量,温度24～28℃,雨日多,田间湿度大,有利于此病发生与流行,发病最重,病情指数为42.5。车前草施用生物有机肥＋叶面肥的病情指数最低,产量最高。发病初期,喷洒爱苗3000倍液,防治效果最佳,其防效为90.8%。     

Short‐term residual N unaffected by forbs in grass‐clover mixtures

We determined the effect on residual nitrogen (N) of including forbs (chicory, ribwort plantain and caraway) in perennial ryegrass‐red clover mixtures. Although soil N inputs during the grassland phase differed markedly between mixtures, in a pot experiment we found no differences in the potentially mineralizable N of the soil or in the dry matter production and N content of the spring barley test crop. The fertilizer value of the grassland mixtures corresponded to 10 g N/m², irrespective of forb inclusion. Thus, the inclusion of nonlegume forbs did not negatively affect short‐term residual N fertility of legume‐based grasslands.     

Variability in reproductive fitness and virulence of four Radopholus similis nematode populations associated with plantains and banana (Musa spp.) in Uganda

Burrowing nematodes (Radopholus similis) are among the most serious nematode pests affecting banana and plantain (Musa spp.). In Uganda, bananas, which are known locally as “matooke”, are the main staple. Radopholus similis populations collected in four banana-growing locations (Namulonge, Mbarara, Ikulwe and Mukono) were cultured monoxenically on carrot discs, and we compared the variability in reproductive fitness and virulence (as a function of time and inoculum level) of different populations of R. similis from Uganda. Their level of pathogenicity was determined by assessing the nematode reproductive ratio; that is, final population divided by the initial population. These in vitro experiments showed that the R. similis population from Mbarara had the highest reproduction ratio, while the population from Mukono had the lowest reproduction ratio. This assessment along with pathogenicity experiments on host Musa plants provides a means for defining pathogenicity groups among R. similis populations.     

Tackling black leaf streak disease and soil fertility constraints to enable the expansion of plantain production to grassland in the humid tropics

In Central Africa, plantain is traditionally grown after a forest fallow. Given increasing urban demand and a lack of forest fallows near urban centres, as well as poor roads and environmental concerns to reduce pressure on forests, research is needed to identify suitable shade, fertility management and cultivars to shift production of plantain to grasslands and to reduce losses to diseases such as black leaf streak disease (BLSD). Effects of light level (full, 67%, 33% light), and nitrogen (N)-amendment on BLSD-tolerant (FHIA-21) and BLSD-susceptible (Batard) cultivars planted on soil from paired grassland and forest sites were determined. BLSD and growth were monitored until 5 months after planting. Three months after planting, leaf area attacked on cultivar FHIA-21 was less than half that on Batard. Plants grown under 33% and 67% light had less leaf area attacked (2.9% and 4.6%, respectively) than those grown in full light (7.3%). Leaf area and dry matter (DM) were higher under shade and when grown on forest soils. Compared to growing BLSD-susceptible plantain on forested land under shade, a shift onto grasslands and a reduction in shade use is predicted to reduce yields. Using cultivar FHIA-21 may limit, but not eliminate, yield loss.     

Effect of ploidy on stomatal and other quantitative traits in plantain and banana hybrids

Summary Ploidy polymorphism occurs in the hybrid offspring derived from interspecific crosses between triploid plantains (Musa spp. AAB group) and diploid bananas (M. acuminata). Therefore,Musa breeders are interested in the determination of ploidy and its effects on phenotypic expression of quantitative traits. The aim of this research was to examine the reliability of stomatal and other phenotypic traits to determine ploidy in segregating plantainbanana hybrid families. Stomatal density and size were significantly correlated (P<0.01) with ploidy, although the correlation coefficients were not high (r=–0.49 and r=0.47, for stomatal density and size, respectively). High density of small stomata was correlated with low ploidy level, and vice versa. However, stomatal size and density were also influenced by a significant genotype effect (P<0.001) within the same ploidy level. Ploidy had an important effect on fruit traits and plant height in the hybrids of Obino l'Ewai×Calcutta 4, but this was not so clear in Bobby Tannap×Calcutta 4 hybrids. Obino l'Ewai derived tetraploids have medium to tall plants with large bunches and big fruits. Most of the tetraploids derived from Bobby Tannap have short stature due to the gene action of the dwarf,dw, allele. Also, a few selected diploids derived from Bobby Tannap outyielded their non-selected tetraploid full-sibs. In conclusion, chromosoem counting remains the only accurate proof of ploidy levels inMusa germplasm.     

Development and performance of balck sigatoka-resistant tetraploid hybrids of plantain (Musa spp., AAB group)

Summary A strategy to control the black sigatoka disease (Mycosphaerella fijiensis Morelet) of plantain (Musa ssp., AAB grou) in Africa, targeting the incorporation of durable host plant resistance, was initiated at the International Institute of Tropical Agriculture (IITA). The commonly accepted intractability of plantain to genetic improvement has been challenged by the identification of 37 different, seed-fertile plantain cultivars and by the production of 250 hybrids in four years of breeding work. Twenty tetraploid hybrids have been selected for their increased black sigatoka resistance, high yields, large parthenocarpic fruits and improved ratooning. Calcutta 4 (Musa acuminata spp. burmannicoides) was the diploid male parent of 17 of the selected hybrids, which indicates that the inferior bunch characteristics of this wild banana were generally not transmitted to its tetraploid progenies. Conversely, the 4x progeny of plantain readily expressed black sigatoka resistance when crossed with Calcutta 4. Progenies of the triploid plantain cvs. Obino l'Ewai and Bobby Tannap differed in their black sigatoka breeding values, the former producing larger numbers of promising hybrids. Tetraploids obtained from crosses of plantain cultivars with the homozygous Calcutta 4 displayed variation in black sigatoka reaction, qualitative morphological traits and growth and yield parameters, suggesting the occurrence of segregation and recombination during the modified megasporogenesis leading to the formation of 2n eggs in the triploid female plantain parents. The variation in black sigatoka reaction among the tetraploid progenies of plantain suggests that resistance could be regulated by recessive, additive genes.     

不同定植期对东莞中把大蕉生长特性的影响

研究了春、夏、秋季不同定植期对东莞中把大蕉生长特性的影响。结果表明,春植蕉营养生长较快,果实生长发育缓慢;夏、秋植蕉营养生长缓慢,果实生长发育较快;各处理全生育期408～424 d,差异不大;单株产量和可溶性固形物含量与定植时期、抽蕾时期、收获时期之间存在显著的相关性,其中春植蕉产量较高、品质较好。     

中国传统文化中“玉簪”原植物的研究

玉簪花是目前国内常见的观赏植物,同时在历史上也有不少记载。为研究中国历史典籍中记载的“玉簪”以及与“玉簪”有关的植物的原植物科学名称以及分类学地位,通过整理在历史典籍中出现的“玉簪”,以及与该名称相关的植物的原始记载、原始插图等各种信息,利用植物分类学的思想,结合比较形态学的分析方法,确定“玉簪”的原植物为百合科玉簪属的Hosta plantaginea (Lam.) Aschers.。对“玉簪”原始资料的整理,揭示尽管中国先民没有建立起一套完整而科学的植物分类体系,但是依然准确而清晰地记述了不少重要的植物分类学信息。同时,根据“玉簪”的“傅面助妆”的记载,整理出中国古代妆容中主要饰品胭脂的植物性原料,结合先民对“玉簪”的认识,揭示出“玉簪”原植物本身的植物学特点,是该种植物为人类选择使用的主要原因。