Quantifying Storage Root Initiation, Growth, and Developmental Responses of Sweetpotato to Early Season Temperature

Abstract

Temperature impacts several growth and developmental processes in sweetpotato [Ipomoea batatas L. (Lam)] including storage root (SR) initiation. To quantify early season growth and developmental responses of sweetpotato, an experiment was conducted using sunlit growth chambers at a wide range of day/night temperatures, 20/12, 25/17, 30/22, 35/27, and 40/32°C, from transplanting to 59 d using cultivar Beauregard. Growth and developmental rates were estimated from plants harvested at regular intervals. Total and SR numbers recorded at each harvest were analyzed by tting sigmoidal curves to estimate SR initiation rates. With increasing temperature, SR conversion e ciency increased quadratically with an optimum at 23.9°C. Adventitous and SR developmental rates were increased linearly and quadratically, respectively, with increasing temperature, and maximum rate of SR initiation was reached at 29.5°C in 16.7 d. Vine and leaf area growth rates showed quadratic trends with temperature with maximum rates at 29 and 33°C, respectively. While quadratic functions best described temperature responses of total, stem, and SR biomass, the optimum temperatures varied among them at 29.2, 30.1, and 26.5°C, respectively. Leaf biomass, conversely, increased linearly with temperature. Fraction of biomass partitioned to roots declined linearly and at high temperature it declined by 75%, compared to the fraction at SR optimum temperature. e SR production e ciency declined from 0.43 to 0.08 g SR kg -1 total weight, and dropped by 81% at high temperature relative to optimum. uanti ed growth and developmental responses derived from the developed temperature-dependent functional algorithms will be useful to develop sweetpotato crop models and management decisions.

Sweetpotato Responses to Mid‐ and Late‐Season Soil Moisture Deficits

“…The midday LWP strongly correlated with soil moisture content. However, potential growth and developmental functions under a wide range of temperatures under optimum water and nutrient conditions (Gajanayake et al, 2014b(Gajanayake et al, , 2015 and with varietal differences are needed for the models to be used for natural resource management. Total chlorophyll content, CMT, and CSI declined with declining LWP, while carotenoid content increased with declining LWP.…”

“…Also, the functional relationships between soil moisture and growth and developmental parameters could be incorporated into existing sweetpotato simulations models (Villordon et al, 2009;Somasundaram and Mithra, 2008) for field-level irrigation scheduling decisions. However, potential growth and developmental functions under a wide range of temperatures under optimum water and nutrient conditions (Gajanayake et al, 2014b(Gajanayake et al, , 2015 and with varietal differences are needed for the models to be used for natural resource management.…”

Sweet potato production in a short-season area utilizing black plastic mulch: effects of cultivar, in-row plant spacing, and harvest date on yield parameters

“…Storage roots are initiated within the first few weeks after planting (Lowe and Wilson 1974). This growth period is greatly influenced by temperature (Gajanayakea et al 2014b). Rapid growth in root size starts at about eight to 10 weeks after planting and continues until harvest or until temperatures become too cold for further growth (Lebot 2009).…”

Gene Regulatory Network Guided Investigations and Engineering of Storage Root Development in Root Crops

“…In root crops, numerous factors have been reported to affect storage root formation, such as temperature (Gajanayake et al, 2014), water deficiency (Solis et al, 2014;Daryanto et al, 2016), nutrient deficiency (Villagarcia et al, 1998;Villordon et al, 2013), and hormones (Radin and Loomis, 1971;Jang et al, 2015).…”