This study assessed the effects of slope exposure, altitude and yield on several cup quality criteria of coffees from two altitude terroirs of Costa Rica, Orosi (between 1020 and 1250 m above sea level) and Santa María de Dota (between 1550 and 1780 m above sea level). East-facing slopes gave beverages with generally superior attributes, probably owing to better exposure to morning sunlight. These beverages were mainly more acid: at Orosi an acidity score of 2.73 out of 5 was obtained (3.64 for Santa María de Dota) for eastern exposures, as opposed to 2.36 on average (3.28 for Santa María de Dota) for other exposures. In addition, a positive relation was found between altitude and taster preferences in both terroirs. A negative relation was also found between yield and beverage acidity at Santa María de Dota, where some coffee trees produced up to 13 kg of coffee cherry. Coffees from Orosi were characterised by a floral flavour, which depended on slope exposure, whilst coffees from Santa María de Dota displayed a chocolate taste, which was more marked at high altitude. In both terroirs the caffeine, trigonelline, fat, sucrose and chlorogenic acid contents were not well correlated with the sensory characteristics.

lations were reported for IVDMD with leaf/stem ratio and number of vascular bundles (Shenk and Elliot, 1970, Major objectives for alfalfa (Medicago sativa L.) breeding include 1971). Negative correlations were reported for lignin improving forage quality and levels of disease resistance. Little is known about the associations between forage quality characteristics, with leaf/stem ratio and stem height (Kephart et al., including pectin (the main component of neutral detergent-soluble 1989, 1990). Johnson et al. (1994) found positive correlafiber [NDSF]), and disease resistance and vigor in alfalfa. Our objections for CP with leaf/stem ratio and lodging, and negatives were to determine, in two alfalfa populations, the (i) correlations tive correlations for CP and regrowth height. Moderate among NDSF and other forage quality traits; (ii) correlations of forage or no associations have been reported for yield with quality traits with plant persistence, vigor, and levels of resistance to NDF, ADF, lignin, IVDMD, and CP (Coors et al., 1986; diseases; and (iii) heritabilities and expected gains from selection for Gil et al. 1967;Hill and Barnes, 1977; Hill, 1981; Kephart the aforementioned traits. Simple, phenotypic, and additive genetic et al., 1989; Shenk and Elliot, 1970; Sumberg et al., correlation coefficients were estimated from half-sib (HS) progeny 1983). Studies on NDSF and associations with other tests of two alfalfa populations (NY9505 and NY9515). In both populations, NDSF was negatively correlated with acid detergent fiber quality constituents and plant characteristics have not (ADF), lignin, and neutral detergent fiber (NDF), and positively corbeen conducted. related with true in vitro dry matter digestibility (IVDMD). Vigor Very few studies have addressed the association bewas positively correlated with ADF, lignin, and NDF, and negatively tween levels of disease resistance and forage quality correlated with IVDMD and crude protein (CP) only in NY9515. Of traits in alfalfa. Some researchers have suggested, with-144 correlation coefficients computed between forage quality traitsout supporting data, that plants selected for higher lignin and resistances to five major alfalfa diseases, only six were significant, and NDF are more vigorous and persistent in the field and they were low in magnitude (Ϫ0.22 Ϯ 0.11 to 0.30 Ϯ 0.14). In than plants selected for lower lignin and NDF (Buxton an alfalfa improvement program, selection for forage quality is not

crude protein, and low fiber concentrations are the results of 20 yr of research in breeding alfalfa for higher Increasing neutral detergent-soluble fiber (NDSF) concentration forage quality and consequently higher digestibility. Inhas been considered a strategy for breeding alfalfa (Medicago sativa L.) with improved quality. Pectin is the main component of NDSF creasing digestibility by increasing pectin concentration and is highly digestible, but the assay for NDSF is time-consuming. has been considered a new strategy for breeding alfalfaThe objectives were (i) to determine the potential use of near infrared with superior quality characteristics (Hatfield, 1996; reflectance spectroscopy (NIRS) to predict NDSF concentration in Van Soest, 1995;Viands, 1995a Viands, , 1995b. Pectin is the alfalfa and (ii) to estimate NDSF heritability and gain from selection. predominant component of NDSF in alfalfa (Hall et al., Herbage was sampled five times across 2 yr from two populations of 1997; Van Soest et al., 1991). Neutral detergent-soluble half-sib (HS) progeny tested at Ithaca, NY. Calibration equations fiber refers to the portion of the forage soluble in neutral were developed by multiple linear regression of laboratory values of detergent solution and resistant to mammalian enzymes, NDSF on NIRS spectra. Samples from one harvest were assayed twice and contains the pectin, ␤-glucan, and fructan fiberto compare extraction methods. Means of NDSF from 90-and 80%fractions (Van Soest et al., 1991). A high NDSF concenethanol extractions were 213.1 Ϯ 7.21 and 179.5 Ϯ 5.89 g kg Ϫ1 , respectively. Assay standard deviations were low for both ethanol concentra-tration in alfalfa forage is desirable because: (i) alfalfa tions. Because a better calibration equation was obtained with the pectin is rapidly and completely fermented by rumen 80%-ethanol assay, all remaining samples were assayed by that techmicroorganisms, providing a better utilization of the nique. Standard errors of calibration were small, ranging from 4.71high protein levels in current cultivars; (ii) pectin ferto 7.54 g kg Ϫ1 . Coefficients of multiple determination (R 2 ) ranged from mentation does not decrease the ruminal pH, often asso-0.72 to 0.97. Most heritability estimates for NDSF were significantly ciated with animal acidosis; and (iii) pectin is not subject greater than zero, ranging from Ϫ0.03 Ϯ 0.20 to 0.56 Ϯ 0.17 and standard error of calibration; SEL, standard error of laboratory deter-

Core Ideas The cultivars Tamani and Zuri have greater nutritive value than cultivar Massai.The individual cattle performance was greater in Tamani and Zuri pastures.Massai provided the same liveweight gain per area than Tamani and Zuri.Tamani and Zuri can be used in grazing systems aiming cattle growing and fattening.Tamani can minimize usual guineagrass restrictions during rainy‐dry season transition. The development of forage cultivars suitable for the Brazilian Cerrados should incorporate long‐term cattle performance results, ensuring released material be persistent and of high quality. The objective of the study was to evaluate the effect of three guineagrass [Megathyrsus maximus (Jacq.) B. K. Simon & S. W. L. Jacobs] cultivars (Massai, Tamani, and Zuri) on liveweight gain of young Nellore (Bos indicus) bulls under grazing. The trial was performed in Planaltina (Federal District, Brazil) from 2011 to 2013 encompassing dry and rainy seasons. Cattle average daily gain (ADG) in the rainy season differed among cultivars, averaging 0.716, 0.791, and 0.883 kg head−1 d−1 for Massai, Tamani, and Zuri, respectively. The ADG was lesser (0.284 kg head−1 d−1) in the dry season with no effects of cultivar. Massai had a similar stocking rate (SR) as Tamani but a greater SR than Zuri in the rainy season (490, 445, and 417 animal unit day ha−1), which was influenced by its greater herbage accumulation rate (HAR; 66.8, 41.4 and 42.3 kg DM ha−1 d−1, respectively). However, there were no differences among cultivars in liveweight (LW) gain per area (GA 2.28 kg ha−1 d−1). In vitro dry matter digestibility (IVDMD) was lesser for Massai (530 g kg−1) compared to Tamani and Zuri (561 and 550 g kg−1, respectively). Due to above‐average nutritive value, Tamani and Zuri provided greater individual cattle performance than Massai, although the GA was similar among all cultivars.

ABSTRACT. Selection of superior forage genotypes is based on agronomic traits assayed in repeated measures. The questions are how repeatable the performance of individual genotypes is and how many harvests are needed to select the best genotypes. The objectives were to estimate repeatability coefficients of dry matter yield (DMY) and forage quality, their phenotypic stability and the number of harvests needed for an accurate selection. Two randomized complete block design experiments data with 24 genotypes each, undergoing 12 and 16 harvests, over a period of 2 and 3 years, respectively, were used. The DMY repeatability estimates ranged from 0.42 to 0.55, suggesting a low heritability. The mean numbers of repeated measures were 5 and 7 harvests for 0.80 and 0.85 accuracy, respectively. The inclusion of the first two harvests negatively affects the estimates. Repeatability for quality traits ranged from 0.30 to 0.69, indicating low to moderate heritability.Keywords: repeated measures, selection efficiency, selection effectiveness.Repetibilidade, número de colheitas e estabilidade fenotípica da produção de matérica seca e de características de qualidade de Panicum maximum jacq. RESUMO.A seleção de genótipos superiores em forrageiras é feita para características agronômicas analisadas em medições repetidas no tempo. As questões estão relacionadas à repetibilidade do desempenho dos genótipos e ao número necessário de colheitas para selecionar aqueles superiores. Os objetivos foram estimar coeficientes de repetibilidade da produção de matéria seca (PMS) e de características de qualidade da forragem, a estabilidade fenotípica e o número de colheitas necessárias para uma seleção mais precisa. Dois experimentos em blocos casualizados com 24 genótipos cada um, submetidos a 12 e 16 colheitas, durante um período de dois e três anos, respectivamente, foram utilizados para o estudo. As estimativas de repetibilidade de PMS variaram de 0,42 a 0,55, sugerindo baixa herdabilidade. Os números de colheitas foram cinco e sete para 0,80 e 0,85 de acurácia, respectivamente. A inclusão das duas primeiras colheitas afeta negativamente as estimativas de PMS. A repetibilidade para as características de qualidade variou de 0,30 a 0,69, indicando baixa à moderada herdabilidade.Palavras-chave: medidas repetidas, eficiência de seleção, eficácia de seleção.