Circular 79

The development of improved cultivars of barley is accomplished through comprehensive plant breeding programs. Such programs: 1). evaluate genetically-diverse germplasm in order to identify superiorperforming genotypes; 2). create new genetic recombinations from crosses or other means using selected parental genotypes; 3). evaluate segregating progeny from these families while exerting selection pressure for desirable characteristics; and 4). identify superior-performing cultivars in yield trials conducted at multiple locations over years. This circular documents the current status of research in cultivar development associated with the Alaska barley breeding program

Regions of the genome that affect agronomic performance in two-row barley

Quantitative trait locus (QTL) main effects and QTL by environment (QTL × E) interactions for seven agronomic traits (grain yield, days to heading, days to maturity, plant height, lodging severity, kernel weight, and test weight) were investigated in a two-row barley (Hordeum vulgare L.) cross, Harrington/TR306. A 127-point base map was constructed from markers (mostly RFLP) scored in 146 random double-haploid (DH) lines from the Harrington/TR306 cross. Field experiments involving the two parents and 145 random DH lines were grown in 1992 and/or 1993 at 17 locations in North America. Analysis of QTL was based on simple and composite interval mapping. Primary QTL were declared at positions where both methods gave evidence for QTL. The number of primary QTL ranged from three to six per trait, collectively explaining 34 to 52% of the genetic variance. None of these primary QTL showed major effects, but many showed effects that were consistent across environments. The addition of secondary QTL gave models that explained 39 to 80% of the genetic variance. The QTL were dispersed throughout the barley genome and some were detected in regions where QTL have been found in previous studies. Eight chromosome regions contained pleiotropic loci and/or linked clusters of loci that affected multiple traits. One region on chromosome 7 affected all traits except days to heading. This study was an intensive effort to evaluate QTL in a narrow-base population grown in a large set of environments. The results reveal the types and distributions of QTL effects manipulated by plant breeders and provide opportunities for future testing of marker-assisted selection

Research Progress Report, No. 26

Barley is the cereal crop best adapted to Alaska’s cool, short-season environment. Not surprisingly, barley is the most important agronomic feed crop in many north-latitude regions which experience similar growing season limitations. Results from longterm yield trials have demonstrated the consistently high yield potential of barley in Alaska. However, the lack of available markets and other economic considerations have limited the extent of its cultivation. An alternative use for barley in Alaska would help provide additional in-state markets. One such use is the production of Alaskagrown barley for use in locally brewed beers. No research trials which investigate the malting quality of Alaska-grown barley are available. This study provides a preliminary assessment of the quality of malt barley produced in Alaska

Testes de capacidade de expansão em programas de melhoramento de milho pipoca Popping expansion tests in popcorn breeding programs

No desenvolvimento de populações melhoradas de milho pipoca é fundamental selecionar com base em qualidade, normalmente expressa pela relação volume de pipoca/peso de grãos, denominada capacidade de expansão (CE). Na seleção de indivíduos e progênies diversos sistemas de avaliação de qualidade devem ser considerados, por serem utilizados pelos consumidores. O propósito deste trabalho foi avaliar dois sistemas de determinação de CE em programas de melhoramento, sendo o primeiro uma pipoqueira de ar quente e o segundo um forno de microondas. Para avaliar a pipoqueira de ar quente foi instalado um experimento no delineamento inteiramente casualizado, envolvendo três tratamentos e nove níveis de peso de grãos, com cinco repetições. Para o microondas, buscando definir uma embalagem alternativa, foi instalado um experimento no delineamento inteiramente casualizado, seguindo um esquema fatorial, com três repetições, envolvendo dois tempos e cinco embalagens. Foi realizado um outro experimento, buscando verificar a qualidade do aparelho para obtenção de CE a partir de pequena quantidade de grãos e qual o melhor tempo a ser utilizado. A pipoqueira de ar quente é um sistema eficiente, podendo ser empregados 10 g na avaliação de plantas e até 90 g para avaliações experimentais de famílias. O forno de microondas é também um sistema eficiente, equivalente à pipoqueira de ar quente. No aparelho de microondas, pode-se empregar saco de papel kraft. Para avaliação de plantas, podem ser empregados 10 gramas e 140 segundos, e 30 a 90 gramas com tempo de 220 segundos para a avaliação de progênies.<br>Quality, normally expressed by the relation volume of popcorn/weight of grains (volume expansion), is an important characteristic in popcorn breeding. Different systems of assessing popcorn expansion should be used in individual and family selections, since they are common to consumers. The purpose of this work was to evaluate two systems for popping expansion determination in breeding programs. The first was a hot air popcorn pumper and the second was a microwave oven. For the first one an experiment was installed in a completely randomized design, with three treatments and nine levels of kernel weight, and five replications. For the second one, aiming to define an alternative packaging, an experiment was installed also in a completely randomized design, following a factorial scheme, with three replications, involving two times and five packagings. Another experiment was achieved to verify the microwave oven quality for volume expansion determination with a little kernel quantity and the best time to be used. The hot air popcorn pumper is an efficient system, in which 10 g of kernel can be used to evaluate plants and up to 90 g of kernel can be used to evaluate families in the experiments. The microwave oven is equivalent to the hot air popcorn pumper. Kraft paper bags can be used in the microwave oven. For plant evaluation 10 g of kernel with 140 seconds are recommended. To evaluate progenies 30 g to 90 g of kernel with 220 seconds can be used

Conceito de ideotipo e seu uso no aumento do rendimento potencial de cereais The ideotipe concept and its use to increase cereal's yield potential

A presente revisão tem por objetivo apresentar algumas características consideradas interessantes de serem incorporadas em plantas de cereais quando cultivadas em comunidade, através da integração de conhecimentos de fisiologia, bioquímica e melhoramento. No melhoramento de diferentes espécies verifica-se que várias características de planta foram modificadas no processo de seleção para rendimento de grãos. Neste enfoque, propõe-se discutir a validade de incorporar estas características em cultivares e perguntar se as cultivares antigas tivessem sido melhoradas através destas características qual resultado teria sido alcançado. A discussão de ideotipo aumenta de importância com a rápida evolução das técnicas de avaliação da variabilidade genética, pois caso não seja definido um modelo de planta para aumentar o rendimento potencial estas técnicas podem ter uma utilização restrita. Na discussão de ideotipo para aumentar o rendimento potencial, é necessário formular um novo modelo baseado em algumas características já amplamente analisadas deforma isolada. As principais, são o maior crescimento inicial e maior fitomassa da comunidade, o que lhe permite aumentar a capacidade de aproveitamento da radiação, principalmente no início do ciclo da cultura. Somado a isto, o aumento da capacidade fotossintética através do aumento da força de demanda, com provável efeito sobre o índice de colheita. A ação conjunta das características individuais necessita ser testada quando incorporadas sobre um mesmo genótipo, para analisar o seu grau de resposta.<br>This review has the purpose of presenting some important traits to be incorporated in cereals through the integration of physiology, biochemistry and plant breeding. Several plant attributes were modified during the selection process to improve grain yield of different plant species. This paper intends to discuss the validity of aggregating some of the se traits in new cultivars and to pinpoint the possible consequences of using those individual characteristics rather than grain yield per se to bred the old genotypes. Discussion about crop ideotipes grows in importance with the fast evolution of genetic variability techniques because if a model plant to increase grain yield is not defined all the new genetic technology available may have a narrow practical utilization. This ideotipe was formulated integrating severa! characteristics that have been analyzed individually in the past. Its main proposed features are: (a) higher initial growth and greater communal phytomass, which are both important to improve solar radiation use, particularly during early stages of development, (b) an increase in photosynthetic capacity through the enhancement of sink strength with a probable effèct on harvest index. The collective influence of the suggested traits must be evaluated on different genotypes to analyze the response level obtained