Internal Heat Necrosis of Potato—A Review

Abstract

Non-pathogenic necroses of potato tubers have been described in the literature since the early 20th century using different names including internal rust spot, internal browning, physiological internal necrosis, internal brown fleck, chocolate spot, internal brown spot and internal heat necrosis. These reports very likely describe either the same, or a collection of similar disorders, falling under the general umbrella of "internal necrosis", with the expression of symptoms being significantly altered via genotype by environment interactions. A number of widely-grown cultivars (e.g. 'Russet Burbank', 'Atlantic' and 'Yukon Gold') are susceptible to internal necrosis, making it an economically significant problem. In Atlantic, this syndrome has been termed internal heat necrosis (IHN) in the eastern United States by several investigators because heat and drought are believed to be important triggers of this condition. Investigators in the midwestern and western United States term this same or similar disorder internal brown spot (IBS). IHN and IBS are an internal physiological disorder of potato characterized by brownish red necrotic patches of parenchymal tissue that typically, though not always, occur along and/or inside the vascular ring. Several reports indicate that IHN is most commonly associated with the vascular ring tissue near the apical end of the tuber, but IHN may form anywhere in the tuber. In many cases, it is very difficult to distinguish between IHN and IBS, and several overlapping environmental factors are associated with each of these disorders. High day and night temperatures early in the growing season, combined with low rainfall, have been shown to increase the frequency and severity of IHN and IBS in several cultivars. Considerable research has examined the role of calcium in ameliorating IHN and IBS expression. Much of this work suggests an important role for calcium in the development of IHN, but other biotic and abiotic factors undoubtedly affect IHN and IBS expression. The biochemistry and genetics behind internal necroses of potato have historically been the leastresearched facets of this problem. Research has shown that enzymes involved in protecting cells from oxidative damage may be involved, and heritability studies have demonstrated that broad-sense heritability for IHN resistance is high. This review seeks to outline previous work on physiological internal necroses of potato due to high temperatures, summarize our current knowledge of IHN, and point to new areas of investigation to develop IHN resistant potato varieties.Resumen Desde comienzos del siglo 20 se han descrito en la literatura unas necrosis no patogénicas del tubérculo de papa, usando diferentes nombres, como herrumbre interna, oscurecimiento interno, necrosis fisiológica interna, punto oscuro interno, mancha chocolate, mancha marrón interna y necrosis interna por calor. Estos nombres parecen describir ya sea la misma enfermedad o una colección de desórdenes similares que caen dentro de la descripción general "necrosis ...

Genetic Map and QTL Analysis of Agronomic Traits in a Diploid Potato Population using Single Nucleotide Polymorphism Markers

“…For TER, we identified four QTL on chromosomes I, III, V, and VI. Tuber end rot could be a physiological disorder of potato tubers with similar symptoms as the "internal necrosis" syndrome well described by Yencho et al (2008). In our case, a progressive rot from the stem end of the tuber affecting all periderm, vascular ring, and parenchymal tissue appears after harvest.…”

“…Those genes were located on chromosomes I, II, and VIII. Different studies have also shown that low calcium (Ca) levels could be correlated with increased tuber IHN (Yencho et al, 2008). In our study, QTL in chromosomes I, III, and VI were detected for TER.…”

“…The models and statistical methods for linkage analysis in outcrossing species have been widely developed. In general, the estimation of the recombination frequencies has been based on two‐point (Maliepaard et al, 1997; Ritter et al, 1990; Ritter and Salamini, 1996), three‐point (Ridout et al, 1998; Wu et al, 2002), and different multipoint maximum likelihood methods (Tong et al, 2010; Van Ooijen, 2011). Similarly, QTL models for complex pedigree and biparental outbreed populations have been developed and described (Gazaffi et al, 2014; Tong et al, 2012).…”

“…A microarray analysis of tuber tissue with different levels of IHN identified some differentially expressed candidate genes (McCord, 2009). Since temperature, water relations, and soil nutrients have an important role in the expression of IHN symptoms (Yencho et al, 2008), it was not surprising that some genes, up-or down-regulated in response to cold and heat stress, were found in the microarray analysis. Those genes were located on chromosomes I, II, and VIII.…”

Genetic Covariance of Environments in the Potato National Chip Processing Trial

“…This is justified from a chip processing perspective because tubers are not stored and processed year round at southern locationsthey are processed within a few days of harvest; as a result, resistance to cold-induced sweetening (Sowokinos, 2001) is not a critical trait. Conversely, resistance to internal heat necrosis (Yencho et al, 2008) is important at southern but not northern locations. Figure 4 provides some empirical support for the traditional mega-environments of North vs. South, but there is more variation between southern locations than there is between the mega-environments.…”