Wendy Yactayo

Improving potato drought tolerance through the induction of long-term water stress memory

Knowledge of drought tolerance in potato is limited and very little is known about stress memory in this crop. In the present study, long-term stress memory was tested on tuber yield and drought tolerance related traits in three potato varieties (Unica, Désirée and Sarnav) with contrasted yields under water restriction. Seed tubers produced by plants grown under non-restricted (non-primed tubers) and restricted (primed tubers) water conditions were sown and exposed to similar watering treatments. Tuber yield and leaf greenness of plants from primed and non-primed seeds as well as tuber carbon isotope discrimination (Δ(13)C) and antioxidant activity (AA) responses to watering treatments were compared. Higher tuber yield, both under non-restricted and restricted water regimes, was produced by primed Sarnav plants. The decrease of tuber yield and Δ(13)C with water restriction was lower in primed Unica plants. Long-term stress memory consequently appears to be highly genotype-dependent in potato. Its expression in plants originated from primed tubers and facing water restriction seems to be positively associated to the degree of inherent capability of the cultivar to yield under water restriction. However, other effects of priming appear to be genotype-independent as priming enhanced the tuber AA in response to water restriction in the three varieties.

Improving potato cultivation using siphons for partial root-zone drying irrigation: a case study in the Blue Nile river basin, Ethiopia.

Abstract Partial root-zone drying (PRD) is an irrigation technique which consists of alternating the water supply from one furrow to another, and keeping the other one dry during the weekly alternation period. Studies assessing PRD in potato have reported a 30-50% of water savings with no tuber yield reductions and an increase of antioxidant concentrations and marketable tubers. In this study, we adapted the PRD technique to rural Ethiopian conditions and compared it against the customary (C) irrigation practiced by local farmers. Two PRD alternatives were evaluated; with (PRDs) and without (PRDw) locally made flexible-hose siphons. Only PRDs showed no significant differences in total (35.8±1.6 t ha-1) and marketable (34.2±1.6 t ha-1) tuber yield when compared with customary irrigation (39.4±1.3 and 37.6±1.2 t ha-1 corresponding to total and marketable yield, respectively). The PRDw was more water restricted, showing significantly lower total (29.7±1.1 t ha-1) and marketable (27.6±1.2 t ha-1) yields. PRDs had the benefit of a better control of applied water allowing a saving of 50% of the irrigation water without negatively affecting yield. The use of the siphons PRD technique provides options for saving scarce water and reaching out to many smallholder farmers who are in serious need of irrigation water in the Blue Nile river basin.

Preliminary evidence of nocturnal transpiration and stomatal conductance in potato and their interaction with drought and yield.

The article Preliminary Evidence of Nocturnal Transpiration and Stomatal Conductance in Potato and their Interaction with Drought and Yield, written by David A. Ramírez, Wendy Yactayo, José L. Rolando and Roberto Quiroz, was originally published electronically on the publisher’s internet portal.

Extreme salinity as a challenge to grow potatoes under Mars-like soil conditions: targeting promising genotypes.

One of the future challenges to produce food in a Mars environment will be the optimization of resources through the potential use of the Martian substratum for growing crops as a part of bioregenerative food systems. In vitro plantlets from 65 potato genotypes were rooted in peat-pellets substratum and transplanted in pots filled with Mars-like soil from La Joya desert in Southern Peru. The Mars-like soil was characterized by extreme salinity (an electric conductivity of 19.3 and 52.6 dS m −1 under 1 : 1 and saturation extract of the soil solution, respectively) and plants grown in it were under sub-optimum physiological status indicated by average maximum stomatal conductance 2 O m −2 s −1 even after irrigation. 40% of the genotypes survived and yielded (0.3–5.2 g tuber plant −1 ) where CIP.397099.4, CIP.396311.1 and CIP.390478.9 were targeted as promising materials with 9.3, 8.9 and 5.8% of fresh tuber yield in relation to the control conditions. A combination of appropriate genotypes and soil management will be crucial to withstand extreme salinity, a problem also important in agriculture on Earth that requires more detailed follow-up studies.