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The number of days from seedling emergence to flowering (DTF) is a major consideration in sunflower breeding programs. This is a complex trait determined by the genotype, environmental conditions and interactions. Photoperiod and temperature have major effects on DTF and could be important sources of genotype× environment interaction. The objectives of this(More)
Hybrids with low grain moisture (GM) at harvest are specially required in mid- to short-season environments. One of the most important factors determining this trait is field grain drying rate (FDR). To produce hybrids with low GM at harvest, inbred lines can be obtained through selection for either GM or FDR. Thus, a single-cross population (181 F(More)
Research on adolescent use of substances has long sought to understand the family factors that may be associated with use of different substances such as alcohol, tobacco and marijuana. However, scant attention has been focused on these questions in Latin American contexts, despite growing concerns about substance use among Latin American youth. Using data(More)
BACKGROUND Although much is known about the higher prevalence of anxiety and depressive disorders among adolescent females, less is known about the differential item endorsement due to gender in items of scales commonly used to measure anxiety and depression. AIMS We conducted a study to examine if adolescent males and females from Chile differed on how(More)
OBJECTIVE: Family involvement and several characteristics of parenting have been suggested to be protective factors for adolescent substance use. Some parenting behaviors may have stronger relationships with adolescent behavior while others may have associations with undesirable behavior among youth. Although it is generally acknowledged that families play(More)
Changes in nitrogen (N) economy and N to dry matter (DM) relationships were studied for six cultivars of bread wheat (Triticum aestivum L.) released in Argentina at different times between 1912 and 1980. Experiments were performed on two successive years. N partitioning to reproductive organs was changed both at anthesis and at maturity. Grain N yield (GNY)(More)
The understanding of the changes produced by plant breeding on wheat grain yield and on its determinants, through the study of the behaviour of cultivars released at different times during the breeding process, could be a useful tool to define future selection criteria. The aim of this paper was to examine the genetic improvement effects on bread wheat(More)
Accurate prediction of phenological development in maize (Zea mays L.) is fundamental to determining crop adaptation and yield potential. A number of thermal functions are used in crop models, but their relative precision in predicting maize development has not been quanti ed. e objectives of this study were (i) to evaluate the precision of eight thermal(More)
Associations between quantitative trait loci (QTL) and corn (Zea mays L.) percentage grain moisture at harvest (GM) have been reported in several studies; however, stability of QTL across breeding populations has depended upon the genetic backgrounds evaluated, the generation of progeny evaluated (inbred lines per se (LP) or test crosses (TC)), and/or the(More)
Phosphorus (P) deficiency limits the yield of wheat, particularly by reducing the number of ears per unit of area because of a poor tiller emergence. The objectives of this work were to (i) determine whether tiller emergence under low phosphorus availability is a function of the availability of assimilates for growth or a direct result of low P(More)