Effect of reduced plant height on drought tolerance in rice.

Asadollah Ahmadikhah,Amir Marufinia

doi:10.1007/s13205-016-0542-3

Asadollah Ahmadikhah, Amir Marufinia

Open Access

https://doi.org/10.1007/s13205-016-0542-3

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Abstract

Drought stress due to water deficit is a major problem of rice cultivation as a most drought-sensitive crop plant. A rice mutant line (MT58) was developed after mutagenesis of cv. Neda by ethyl methane sulfonate (EMS) and selected for dwarfism (18 cm shorter than Neda). The extent of its molecular changes relative to parental cultivar was assessed by SSR and ISSR markers, and the response of the line along with parental cultivar and another mutant line (MTA) to mild and severe water deficit, was evaluated in a field experiment. A molecular assessment using 41 SSR markers showed that dwarf line MT58 had significant molecular difference with two other lines. ISSR assay also proved the considerable mutational effect of EMS on two mutant lines compared with the original wild line. Field experiments revealed that limited irrigation caused mild-to-severe decrease in all the studied traits, including chlorophyll contents. In mild water-stress mutant line, MT58 showed a low (3 %) yield loss as compared with cultivar Neda with a high (14 %) yield loss. Interestingly, in severe water-stress mutant line, MT58 showed a low (19 %) yield loss as compared with mutant line MTA and cv. Neda with high (33 and 31 %, respectively) yield loss. In severe stress, mutant MT58 had the highest values of panicle length, total kernels per panicle, fertile kernels, and chlorophyll contents, while cv. Neda had the highest values of plant height, tiller number, and plant yield, and reduction in chlorophyll content at drought stress condition was correlated with yield loss (0.64 and 0.697 for chl.a and chl.b, respectively). The results of this research obviously confirm that mutant line MT58 despite of its stunt figure shows a low yield loss due to drought stress and hence is a promising line for cultivation under drought condition.Electronic supplementary materialThe online version of this article (doi:10.1007/s13205-016-0542-3) contains supplementary material, which is available to authorized users.

Highlights

Abiotic stresses especially drought can affect the physiological status of an organism and have adverse effects on growth, development, and metabolism (Chutia and Borah 221 Page 2 of 92012)
Since water availability will be a major constraint for paddy rice productivity in the near future, we studied the response of a dwarf mutant line of rice along with its parental cultivar to water deficit aiming to evaluate effect of dwarfism on morphophysiological traits, plant yield in a field experiment
Mutant line MT58 showed different banding patterns in 7 out of 41 simple sequence repeat (SSR) loci, including RM1, RM3510, RM3233, RM1146, RM206, RM3873, and RM505. Most of these polymorphic SSRs have dinucleotide AG or GA repeated motifs; the exceptions are RM505 and RM3510 with dinucleotide CT repeat Cluster analysis placed the mutant line MT58 in a separate group and two lines Neda and MTA in another group with[90 % bootstrap support (Fig. 1 top); in addition, the grouping was validated by a high cophenetic correlation coefficient (r = 0.968)

Summary

Introduction

Abiotic stresses especially drought can affect the physiological status of an organism and have adverse effects on growth, development, and metabolism (Chutia and Borah 221 Page 2 of 92012). Drought is an abiotic stress which affects plants at various levels and stages of their life period This abiotic stress affects plant–water relations through the reduction of water content, turgor, and total water, but it affects stomatal closure, limits gas exchange, reduces transpiration, and disturbs photosynthesis (Razak et al 2013). Rice varieties have differential responses to abiotic stresses because of the complexity of interactions between stress factors and various molecular, biochemical, and physiological processes that affect plant growth and development (Zhu 2002; Wadhwa et al 2010). Cha-um et al (2010) reported differential responses of rice genotypes to water deficit They observed when rice genotyped exposed to water deficit, panicle length and fertile grains in two tolerant varieties were not significantly decreased, leading to greater productivity than in two sensitive cultivars (Chaum et al 2010)

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