ABSTRACT
RESUMEN El cultivo de durazno (Prunus persica (L.) Batsch.) es de gran importancia en la provincia de Pamplona, dada su adaptación a la zona, como un frutal caducifolio. Los modelos matemáticos son relevantes en la agricultura para evitar muestreos destructivos, lo que supone la pérdida de material de investigación y la compra de costosos equipos de medición. Para estimar variables de respuesta de características del fruto del cultivar Jarillo a diferentes altitudes, se llevó a cabo un estudio en el paisaje de montaña de Norte de Santander, Colombia, evaluando 660 frutos desde el inicio de la formación hasta su maduración, a una altitud de 1.670, 1.870 y 2.170 m s.n.m. El rendimiento y el número de frutos totales fue mayor en la menor altitud evaluada. A 1.870 m s.n.m. el contenido de solidos solubles totales fue menor; la relación de madurez tendió a incrementarse en las tres altitudes, pero en menor proporción, para 1.870 m s.n.m. El análisis de regresión lineal múltiple indicó diversos modelos de regresión lineal simple adecuados, según, sea el caso, para estimar sólidos solubles totales, cosecha total y peso fresco del durazno por altitud.
ABSTRACT The peach crop (Prunus persica (L.) Batsch.) is of great importance in the province of Pamplona, due to its adaptation to the area as a deciduous fruit tree. Mathematical models are relevant in agriculture to avoid destructive sampling, which involves the loss of research material and the purchase of expensive measuring equipment. To estimate response variables of fruit characteristics of the Jarillo cultivar at different altitudes, a study was carried out in the mountain landscape of Norte de Santander, Colombia, evaluating 660 fruits from the beginning of fruit formation to fruit ripening at an altitude of 1,670, 1,870, and 2,170 m a.s.l. Yield and number of total fruits were higher at lower altitudes and decreased at higher altitudes. At 1,870 m a.s.l., total soluble solids content was lower. The maturity relation tended to increase at all three altitudes, but to a lesser extent at 1,870 m a.s.l. Multiple linear regression analyses indicated several simple linear regression models suitable for estimating total soluble solids, total yield, and fresh weight of peaches by altitude.
ABSTRACT
BACKGROUND AND AIMS: The implications of herbivory for plant reproduction have been widely studied; however, the relationship of defoliation and reproductive success is not linear, as there are many interacting factors that may influence reproductive responses to herbivore damage. In this study we aimed to disentangle how the timing of foliar damage impacts both male and female components of fitness, and to assess when it has greater impacts on plant reproductive success. METHODS: We measured herbivore damage and its effects on floral production, male and female floral attributes as well as fruit yield in three different phenological phases of Casearia nitida (Salicaceae) over the course of two consecutive years. Then we tested two models of multiple causal links among herbivory and reproductive success using piecewise structural equation models. KEY RESULTS: The effects of leaf damage differed between reproductive seasons and between male and female components of fitness. Moreover, the impact of herbivory extended beyond the year when it was exerted. The previous season's cumulated foliar damage had the largest impact on reproductive characters, in particular a negative effect on the numbers of inflorescences, flowers and pollen grains, indirectly affecting the numbers of infructescences and fruits, and a positive one on the amount of foliar damage during flowering. CONCLUSIONS: For perennial and proleptic species, the dynamics of resource acquisition and allocation patterns for reproduction promote and extend the effects of herbivore damage to longer periods than a single reproductive event and growing season, through the interactions among different components of female and male fitness.