The response of the sugar beet (Beta vulgaris L.ssp. vulgaris var. altissima Döll) genotypes to heat stress in initial growth stage

Abstract

The response of the sugar beet (Beta vulgaris L.ssp. vulgaris var. altissima Döll) genotypes to heat stress in initial growth stage Abstract: The continuous trend of global warming and increasing interest toward cultivating sugar beet (Beta vulgaris L. ssp. vulgaris var. altissima Döll) in tropical regions led us to conduct this study to investigate the effect of high temperature on sugar beet at initial growth stages. Thirty one genotypes were incubated at two temperatures (20 °C and 30 °C) in laboratory for germination test. The same genotypes were assessed for physiological parameters at 30 °C in greenhouse, too. Increasing temperature decreased germination indices with a high variability among the genotypes. Seed vigor index and seminal root length were decreased higher than other indices. The genotypes with higher greenness index had higher total dry mass, leaf area and leaf temperature depression (LTD), and those with higher seed vigor index indicated great quantum efficiency of PSII (Fv/Fm) values. 'S1-92521' produced high records in both laboratory and greenhouse experiments. Although 'S1-92521' showed good tolerance in both laboratory and greenhouse experiments, totally, sugar beet genotypes had different performance at two experiments. According to the results, seed vigor index could be used as a screening tool in laboratory, and LTD and Fv/Fm were considered as good criteria for screening heat-tolerant genotypes in greenhouse. Odziv genotipov sladkorne pese (Beta vulgaris L. ssp. vulgaris var. altissima Döll) na vročinski stres v začetnih fazah rastiIzvleček: Naraščajoči trend globalnega segrevanja in vse večji interes za gojenje sladkorne pese (Beta vulgaris L. ssp. vulgaris var. altissima Döll) v tropskih območjih so privedli k izvedbi te raziskave, v kateri je bil preučevan učinek visokih temperature na sladkorno peso v začetnih fazah rasti. 31 genotipov je bilo inkubiranih pri dveh temperaturah (20 °C in 30 °C) v laboratoriju za kalitvene teste. Na istih genotipih so bili v rastlinjaku ocenjeni fiziološki parametri pri temperaturi 30 °C Povišanje temperature je zmanjšalo indekse kalitve z veliko spremenljivostjo med genotipi. Indeks vitalnosti semen in dolžina semenske korenine sta se bolj zmanjšala kot drugi indeksi. Genotipi z večjimi indeksi zelenosti so imeli večjo celokupno suho maso, večjo listno površino in večji upad temperature listov (LTD), genotipi z večjimi indeksi vitalnosti semen so pokazali velike vrednosti kvantne učinkovitosti PSII (Fv/Fm). 'S1-92521'je imel velike vrednosti vseh merjenih parametrov tako v laboratoriju kot v rastlinjaku. Čeprav je imel genotip 'S1-92521' dobro tolerance na visoke temperature tako v laboratoriju kot v rastlinjaku, so imeli drugi genotipi sladkorne pese zelo različne odzive v obeh poskusih. Glede na rezultate bi lahko indeks vitalnosti semen uporabili kot primerno orodje za preiskušanje genotipov v laboratoriju, parametra LTD in Fv/Fm pa sta se izkazala kot dober kriterij za preiskušanje genotipov na visoke temperature v rastlinjaku.Ključne besede: p...

An Insight into the Abiotic Stress Responses of Cultivated Beets (Beta vulgaris L.)

“…Critical physiological processes, including photosynthesis and PSII activity, were also affected due to electron transport chain block under heat stress [ 90 , 91 ]. Of late, sugar beet cultivation is also expanding to the tropical and sub-tropical areas, and more people pay attention to cultivation of the sugar beets in summer [ 29 , 92 ]. Ironically, there are few studies aimed to select the heat-tolerant sugar beet cultivars.…”

“…Different research groups used different parameters to evaluate the heat stress tolerance in different beet cultivars. For instance, Malmir et al [ 92 ] considered the seed vigor index and root length as evaluation parameters of heat stress tolerance in the early growth stage [ 92 ]. To investigate the effects of heat on early growth in sugar beet, they compared 31 sugar beet genotypes under heat stress conditions.…”

“…To investigate the effects of heat on early growth in sugar beet, they compared 31 sugar beet genotypes under heat stress conditions. Among all the variants tested, the tolerant genotype displayed relatively higher germination, seed vigor, plumule length, and seedling length compared to other genotypes, suggesting that the tolerant one is a prospective cultivar to expand the sugar beet cultivation to tropical areas [ 92 ]. Under high temperatures, the leaf temperature, which is associated with vapor pressure deficit (VPD) and stomatal conductance, is known to be enhanced [ 93 ].…”