TY - JOUR

T1 - Two potato (Solanum tuberosum) varieties differ in drought tolerance due to differences in root growth at depth

AU - Puertolas Simon, Jaime

AU - Ballester, Carlos

AU - Elphinstone, E. David

AU - Dodd, Ian C.

PY - 2014/8/6

Y1 - 2014/8/6

N2 - To test the hypothesis that root growth at depth is a key trait explaining some genotypic differences in drought tolerance in potato (Solanum tuberosum L.), two varieties (Horizon and Maris Piper) differing in drought tolerance were subjected to different irrigation regimes in pots in a glasshouse and in the field under a polytunnel. In the glasshouse, both cultivars showed similar gas exchange, leaf water potential, leaf xylem ABA concentration and shoot biomass independently of whether plants were grown under well watered or water deficit conditions. Under well watered conditions, root growth was three-fold higher in Horizon compared with Maris Piper, 3 weeks after emergence. Water deficit reduced this difference. In the polytunnel, applying 60% or less irrigation volume compared with full irrigation significantly decreased tuber yield in Maris Piper but not in Horizon. This was coincident with the higher root density of Horizon in deep soil layers (>40 cm), where water content was stable. The results suggest that early vigorous root proliferation may be a useful selection trait for maintaining yield of potato under restricted irrigation or rainfall, because it rapidly secures access to water stored in deep soil layers. Although selecting for vigorous root growth may assist phenotyping screening for drought tolerance, these varieties may require particular environmental or cultural conditions to express root vigour, such as sufficiently deep soils or sufficient water shortly after emergence.

AB - To test the hypothesis that root growth at depth is a key trait explaining some genotypic differences in drought tolerance in potato (Solanum tuberosum L.), two varieties (Horizon and Maris Piper) differing in drought tolerance were subjected to different irrigation regimes in pots in a glasshouse and in the field under a polytunnel. In the glasshouse, both cultivars showed similar gas exchange, leaf water potential, leaf xylem ABA concentration and shoot biomass independently of whether plants were grown under well watered or water deficit conditions. Under well watered conditions, root growth was three-fold higher in Horizon compared with Maris Piper, 3 weeks after emergence. Water deficit reduced this difference. In the polytunnel, applying 60% or less irrigation volume compared with full irrigation significantly decreased tuber yield in Maris Piper but not in Horizon. This was coincident with the higher root density of Horizon in deep soil layers (>40 cm), where water content was stable. The results suggest that early vigorous root proliferation may be a useful selection trait for maintaining yield of potato under restricted irrigation or rainfall, because it rapidly secures access to water stored in deep soil layers. Although selecting for vigorous root growth may assist phenotyping screening for drought tolerance, these varieties may require particular environmental or cultural conditions to express root vigour, such as sufficiently deep soils or sufficient water shortly after emergence.

KW - abscisic acid

KW - deficit irrigation

KW - genotypic selection

KW - partial rootzone drying

KW - variety

KW - CARBON-ISOTOPE DISCRIMINATION

KW - ZONE DRYING IRRIGATION

KW - WATER-USE EFFICIENCY

KW - ABSCISIC-ACID

KW - SOIL-MOISTURE

KW - DEFICIT IRRIGATION

KW - GAS-EXCHANGE

KW - YIELD

KW - CROP

KW - L.

U2 - 10.1071/FP14105

DO - 10.1071/FP14105

M3 - Journal article

VL - 41

SP - 1107

EP - 1118

JO - Functional Plant Biology

JF - Functional Plant Biology

SN - 1445-4408

IS - 10-11

ER -