D. Sienkiewicz-Paderewska

Forages: Ecology, Breeding Objectives and Procedures

Forages are integral components of grassland and pasture agro-ecosystem. They are the major source of feed and nutrition for livestock. As primary producers, they are converted by livestock into secondary production in the food chain. Forage breeding is a complex process involving plant morpho-physiological aspects (perenniality, mode of reproduction, mating systems) and aberrant plant-environment correlations affecting plant performance under various sward conditions. The ultimate aim of forage breeding is to develop cultivars with high and sustainable herbage yield under various management systems. It also encompasses development of cultivars with beneficial impacts on ecosystem functions, animal growth and health. This chapter addresses challenges for forage producers and breeders due to rapidly diminishing grassland areas and the impact on the biodiversity of grassland ecosystems and their productivity. Approaches to conserve genetic diversity and utilize forage genetic resources in an efficient way as well as breeding procedures practical use in selected forage crops are discussed.

Multitraits evaluation of Pakistani ecotypes of berseem clover ( Trifolium alexandrinum L.) under full-irrigation and water restriction conditions

Summary Berseem clover ( Trifolium alexandrinum L.) is an important forage crop in Pakistan and many ecotypes are grown across the country. Its yield is however frequently affected by insufficient irrigation due to unavailability of water. In the present study, twenty Pakistani ecotypes of berseem clover have been evaluated in lysimeters under full irrigation and water restriction conditions. In the full irrigation treatment soil humidity was maintained at field capacity, while in the water restriction treatment water was only supplied after severe wilting and to maintain humidity in the deep profile of the soil. Assessed traits included forage yield, calculated as the sum of the biomass harvested at 70 and 110 DA days after emergence, and morpho-physiological traits. Significant effects of water restriction were noted on yield, leaf gas exchange parameters, canopy temperature and osmotic adjustment. Most morpho-physiological traits had higher broad sense heritability than forage yield, both under full irrigation and water restriction conditions. Water restriction increased genetic and phenotypic variability and heritability of most traits under study. Under these conditions forage yield was positively associated to leaf temperature and recovery rate index and, under full irrigation, to net photosynthetic rate, canopy depression temperature and leaf area. The possible use of these traits as indirect selection criteria in berseem clover breeding programs is discussed. Some ecotypes with favorable traits such as high forage yield potential, good adaptation to water restriction and aptitude to multiple harvesting have also been identified.

Habitat preferences of plant communities: New approach based on the GGE biplot analysis

ABSTRACT In this paper we introduce a new way of analysing habitat preferences of plant communities using the genotype and genotype-by-environment interaction effects (GGE) biplot method. We took into consideration real data on six plant associations belonging to the Molinio-Arrhenatheretea class. A total of 241 phytosociological relevès collected with the Braun-Blanquet method were described by the Ellenberg indicators. The two-way classification relevès-by-indicators was analysed with GGE. As a result it is proposed the modified biplot that contains ellipses for making the plot clearer. Next, we present the equations that described both axes and allow adding into the biplot any other relevès or a mean of set of relevès. Based on the generated biplot it is possible to present an ecological characteristics of any type of plant community including its acceptable and typical habitat requirements. The ellipse ranges provide important information about the homogeneity and ecological spectrum of the analysed syntaxon. The constructed equations allow comparing new data with data analysed previously. Summing up, the GGE biplot method is useful for analysing and graphically presenting ecological preferences of plant communities in a simple and comprehensive way.