Fruit Growth and Development of `Ideal' and `Western' Pecans

Abstract

Pecan [Carya illinoensis (Wangenh.) K. Koch] fruit development was evaluated over three growing seasons (1981-83) to determine the seasonal growth patterns in the cultivars Ideal and Western. Gross morphological stages were examined weekly in fruit dissected in cross and longitudinal sections. Free-nucleate endosperm was first observed in mid-July when fruit had grown to 50% of their final length, occurring at 67 days after stigma receptivity (DASR) for 'Ideal' and 76 DASR for Western'. Maximum content of free-nucleate endosperm occurred 100 DASR in 'Ideal' and 109 DASR in Western' fruit. Ovary wall Signification was completed 119 DASR in 'Ideal' and 132 DASR in 'Western'. At this time, nut enlargement was complete. Cotyledon thickening required 36 and 43 days for 'Ideal' and Western', respectively. The time from stigma receptivity to completion of cotyledon thickening in mid-October was 13 days longer for Western' than for 'Ideal'. Because of a cool spring in 1983, all stages required a longer time in 1983 than in the previous 2 years. Most aspects of fruit development were similar between 'Ideal' and Western' over the 3-year study. -Abbreviations: DASR, days after stigma receptivity IPMS, in plane to the middle septum; IPMSE, in plane to the middle septum extension; RAMS, at right angles to the middle septum.

Midday Stem Water Potential Values Needed to Maintain Photosynthesis and Leaf Gas Exchange Established for Pecan

“…7; Table 2). Herrera (1990) and Wells et al (2007) concluded that low soil moisture during the kernel-filling stage reduces embryo development and kernels do not fill properly. However, our yield data were a case study and we had no mechanism for estimating error.…”

“…Pecan nut development can be divided into two stages: nut sizing and kernel filling (Wells et al, 2007). In nut sizing, the nut enlarges and the volume of endosperm increases (Herrera, 1990). Water deficit during nut sizing diminishes the ability of pecan roots to extract soil water and this reduces growth and nut size and increases nut split (Wells et al, 2007).…”

“…Water deficit during nut sizing diminishes the ability of pecan roots to extract soil water and this reduces growth and nut size and increases nut split (Wells et al, 2007). Low soil moisture during this stage also reduces embryo development, resulting in poor kernel fill (Herrera, 1990;Wells et al, 2007).…”

Programación del riego en nogal pecanero (Carya illinoinensis), mediante un modelo integral basado en tiempo térmico

“…Trees in orchards mismanaged irrigation show low production (0.8 t ha -1 ) and quality (glued husk, walnut germination and lack of fruit filling), which is associated with water stress caused by improper programming irrigation, mainly for almond filling (Stein et al, 1989;Herrera, 1990;Sparks, 1995c).…”

“…Los árboles de las huertas en riegos mal manejados, muestran baja producción (0.8 t ha -1 ) y calidad (ruezno pegado, germinación de la nuez y falta llenado de fruto), que está asociado con estrés hídrico causado por una inadecuada programación de los riegos principalmente en llenado de almendra (Stein et al, 1989;Herrera, 1990;Sparks, 1995c).…”