Tagging quantitative trait loci for heading date and plant height in important breeding parents of rice (Oryza sativa)

Heading date and plant height are important determinants for plant growth rate. In this study, simple sequence repeat markers were used to tag quantitative trait loci (QTL) using a recombinant inbred line mapping population derived from two important breeding parents, genetic stock Kaybonnetlpa1-1 and indica cultivar Zhe733, using data collected under field and greenhouse conditions. Interval mapping, composite interval mapping, and multiple interval mapping were performed to map QTL for heading date and plant height, and to identify epistatic interactions between the QTL. qHD3.1 on chromosome 3 from KBNTlpa1-1 had the largest effect on heading date contributing an average of 28.4 % of the total phenotypic variation. qHD7.1, 7.2, and 8.1 also had a significant contribution to heading date from Zhe733 averaging 8.1, 12.8, and 12.8 % of the phenotypic variance, respectively, and there was a positive additive-by-additive epistatic interaction between qHD7.1 and qHD8.1. QTL, qPHT1.1 and qPHT3.1, for plant height were detected on chromosomes 1 and 3, respectively. qPHT1.1 contributed the largest effect representing 38.2 % of the total phenotypic variation. Comparison of the QTL identified in our study with previous results revealed that the chromosomal locations for QTL coincided closely with positions reported previously in other rice populations worldwide, suggesting that these QTL have coevolved and become domesticated. The tightly linked SSR markers that flank these QTL should be desirable for tagging heading date and plant height genes and facilitating their incorporation into advanced breeding lines using marker assisted selection.     

Voluntary Certification Design Choices Influence Producer Participation,Stakeholder Acceptance,and Environmental Sustainability in Commodity Agriculture Sectors in Tropical Forest Landscapes

Voluntary certification programs are one type of intervention used to incentivize the agricultural commodity sector in tropical landscapes to reduce deforestation and improve sustainability. Cases of the Roundtable on Sustainable Palm Oil (RSPO) voluntary certification program in Indonesia and the Sustainable Agriculture Network (SAN), voluntary certification for cattle in Brazil, are used to contrast the role taken in two significantly different programs to render sustainability outcomes. While producers in both countries follow a similar path toward compliance with certification standards, only the RSPO program offers enticements for producers to participate in the intermediate stages of compliance by offering membership in its affiliated industry roundtable. Design choices about the core activities of a program (adoption, implementation, and enforcement and monitoring) that are ancillary to standards setting are found to be opportunities for providing benefits to both producers and civil society stakeholders without compromising the program’s rigor. A framework is proposed to understand voluntary certification programs as both creators and brokers of benefits between producers and other sustainability stakeholders, potentially providing an approach to simultaneously increase participation and maintain program rigor.     

Relationships in pineapple by random amplified polymorphic DNA (RAPD) analysis

Random amplified polymorphic DNA (RAPD) analysis was applied to eight commercial cultivars of pineapple, two intergroup hybrids and two wild species. Morphologically, pineapple is divided into the Cayenne, Queen, Spanish, Maipure and Abacaxi groups. Members of the first three groups have been analysed in this study. The cultivars ‘Tradsithong’, ‘Phuket’, ‘Sawee’ and ‘Tainan’, with spiny leaves, form the Queen group. In ‘Pattavia’, ‘Nanglae’ and ‘Petburi no. 2’ (Cayenne group), spines are confined to the leaf tips. ‘Intrachitdang’ is normally placed in the Spanish group, which is morphologically similar to the Queen group, but with inferior quality fruit. DNA amplification products were compared from 16 arbitrary 10‐mer primers from which a dendrogram was constructed. The results confirmed morphological classifications for seven of the eight commercial cultivars, with the Queen and Cayenne groups as separate clusters. However, the cv. ‘Intrachitdang’ was more closely related to the Cayenne group. Two hybrids from reciprocal Cayenne × Queen group crosses, were more closely allied to the Queen group. The two wild species were outside the groups. RAPD analysis can be exploited to investigate relationships within pineapple germplasm.     

Cattle affect early post-fire regeneration in a Nothofagus dombeyi-Austrocedrus chilensis mixed forest in northern Patagonia, Argentina

In forest ecosystems where infrequent, severe fires have been an important process in shaping ecosystem structure, understanding the effects of introduced livestock on post-fire recovery of the vegetation is essential for effective forest resource management and preservation. In Nahuel Huapi National Park in northwestern Patagonia, we studied the effects of livestock on the post-fire recovery of a Nothofagus dombeyi-Austrocedrus chilensis forest that was burned in 1999. We experimentally excluded cattle by fencing plots and compared the vegetation characteristics of fenced and unfenced control plots over a 5-year period. Although cattle did not significantly reduce total plant cover or total species richness, they did reduce maximum heights of woody species including the dominant tree species. Chusquea culeou, a tall understory bamboo, can impede establishment and height growth of the dominant tree species. Although C. culeou accounts for the largest percentage of cattle diet, its mean cover and mean maximum height were not strongly affected by cattle. The reduction in the height growth of seedlings of N. dombeyi and Austrocedrus in the unfenced areas implies that presence of cattle in the recently burned areas may contribute to a post-fire transition from tall forest to bamboo-dominated shrubland that is already widespread in this landscape. Thus, these results provide support for the fencing of recently burned Nothofagus and Austrocedrus forests in the national parks for periods long enough to allow the dominant tree species to grow to heights at which they are no longer severely inhibited by cattle browsing.     

Comparing local vs. global visible and near-infrared (VisNIR) diffuse reflectance spectroscopy (DRS) calibrations for the prediction of soil clay, organic C and inorganic C

Local, field-scale, VisNIR-DRS soil calibrations generally yield the most accurate predictions but require a substantial number of local calibration samples at every application site. Global to regional calibrations are more economically efficient, but don't provide sufficient accuracy for many applications. In this study, we quantified the value of augmenting a large global spectral library with relatively few local calibration samples for VisNIR-DRS predictions of soil clay content (clay), organic carbon content (SOC), and inorganic carbon content (IC). VisNIR models were constructed with boosted regression trees employing global, local + global, and local spectral data, using local samples from two low-relief, sedimentary bedrock controlled, semiarid grassland sites, and one granitic, montane, subalpine forest site, in Montana, USA. The local + global calibration yielded the most accurate SOC predictions for all three sites [Standard Error of Prediction (SEP) = 3.8, 6.7, and 26.2 g kg^− 1]. This was similarly true for clay (SEP = 95.3 and 102.5 g kg^− 1) and IC (SEP = 5.5 and 6.0 g kg^− 1) predictions at the two semiarid grassland sites. A purely local calibration produced the best validation results for soil clay content at the subalpine forest site (SEP = 49.2 g kg^− 1), which also had the largest number of local calibration samples (N = 210). Using only samples from calcareous soils in the global spectral library combined with local samples produced the best SOC and IC results at the more arid of the two semiarid sites. Global samples alone never achieved more accurate predictions than the best local + global calibrations. For the temperate soils used in this study, the augmentation of a large global spectral library with relatively few local samples generally improved the prediction of soil clay, SOC, and IC relative to global or local samples alone.     

Milk carbon footprint of silvopastoral dairy systems in the Northern Peruvian Amazon

Tropical Animal Health and Production - The objective of the study was to assess the effects of water deprivation on the burden of gastrointestinal nematodes in Nguni does. A survey was piloted on...     

Will technology provide solutions for drug resistance in veterinary helminths?

Drug resistance in veterinary helminths affects a growing number of livestock producers on a global basis. The parasites infecting the major species of livestock are presently showing resistance in varying degrees to the commonly used classes of anthelmintics. The degree and extent of this problem especially with respect to multidrug resistance (MDR) in nematode populations is likely to increase. Finding solutions to the spread of resistance requires knowledge of the drugs' modes of action and mechanisms of resistance. This knowledge can then be applied to detect and monitor the state of resistance. Here we present a brief overview of resistance mechanisms and some of the technologies being used to study them. We also discuss some of the strategies for slowing the spread of resistance. The issue of reversal of drug resistance is analysed under consideration of recent progress in the field of MDR reversal in non-infectious diseases. Finally, we propose an application of currently available technologies that could assist in the detection and monitoring of anthelmintic resistance. Taking into account the significant complexity of the genetic mechanism of anthelmintic resistance in and between the various species, we suggest to undertake a co-ordinated effort to systematically identify anthelmintic-related single nucleotide polymorphisms (SNPs) in the most important helminth parasites. Monitoring the state of resistance in field populations could be achieved with a SNP-based protocol for genotyping the many genes known or suspected to contribute to the modes of action or mechanisms of resistance to the various classes of anthelmintics. If significant associations between genotypes and phenotypes exist within a species, then a single test with sufficient SNPs could potentially have universal applicability. These could then be explored for the development of new molecular diagnostic procedures. New classes of anthelmintics are needed, but until they are developed and available to the producers, technology can assist to achieve the goal of better sustainability in anthelmintic usage.