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High‐Andean crops are precious resources for low‐income farmers threatened by climate conditions. In the Puna region of the central Peruvian Andes, poor farmers grow maca (Lepidium meyenii Walpers), a root crop endemic to this region, under extreme environmental conditions. The performance ranking of crop accessions may vary with climate variability due to interactions between genotypes and the environment, but this issue has not been addressed for maca crops. Here we used three thermal setups under laboratory conditions and tested the effects of temperature regime, seed accession, and germination promoters on seed germination and seedling performance traits of maca plants. We found significant temperature × accession (T × A) interactions for most response variables, that is, the performance ranking of accessions varied with temperature regimes. The positive effects of promoters (gibberellic acid, GA; sodium hypochlorite, SH) on germination and seedling emergence variables were not additive and showed a clear trend to be greater at lower temperatures. Because available maca accessions still require the Andean Puna´s cold environment to develop their hypocotyls fully, the selection of accessions with better tolerance to higher temperatures should be taken as a long‐term challenge. In the short term, our findings strongly suggest that maca growers might use GA as a promoter to overcome limitations imposed on seed germination and seedling emergence by low temperatures at the crop‐growing areas. Core Ideas: Performance ranking of maca accessions varied among different thermal scenarios.The positive effects of germination promoters was most noticeable at low temperatures.Promoters did not show an additive effect when applied together.Association between germination and seedling emergence was independent of temperature. [ABSTRACT FROM AUTHOR]

High-elevation ecosystems are traditionally viewed as environments in which predominantly autogamous breeding systems should be selected because of the limited pollinator availability. Chaetanthera renifolia (Asteraceae) is an endemic monocarpic triennial herb restricted to a narrow altitudinal range within the high Andes of central Chile (3300-3500 m a.s.l.), just below the vegetation limit. This species displays one of the larger capitulum within the genus. Under the reproductive assurance hypothesis, and considering its short longevity (monocarpic triennial), an autogamous breeding system and low levels of pollen limitation would be predicted for C. renifolia. In contrast, considering its large floral size, a xenogamous breeding system, and significant levels of pollen limitation could be expected. In addition, the increased pollination probability hypothesis predicts prolonged stigma longevity for high alpine plants. We tested these alternative predictions by performing experimental crossings in the field to establish the breeding system and to measure the magnitude of pollen limitation in two populations of C. renifolia. In addition, we measured the stigma longevity in unpollinated and open pollinated capitula, and pollinator visitation rates in the field. We found low levels of self-compatibility and significant levels of pollen limitation in C. renifolia. Pollinator visitation rates were moderate (0.047-0.079 visits per capitulum per 30 min). Although pollinator visitation rate significantly differed between populations, they were not translated into differences in achene output. Finally, C. renifolia stigma longevity of unpollinated plants was extremely long and significantly higher than that of open pollinated plants (26.362.8 days vs. 10.162.2, respectively), which gives support to the increased pollination probability hypothesis for high-elevation flowering plants. Our results add to a growing number of studies that show that xenogamous breeding systems and mechanisms to increase pollination opportunities can be selected in high-elevation ecosystems. [ABSTRACT FROM AUTHOR]

Insects are attracted to plants by visual and olfactory cues. The quinoa moth, Eurysacca melanocampta Meyrick (Lepidoptera: Gelechiidae), is the main insect pest of the quinoa crop, Chenopodium quinoa Wilid. (Chenopodiales: Chenopodiaceae), in the southern Peruvian Andes, causing grain yield losses. The aim of this study was to investigate the behavioural response of adult quinoa moths to olfactory stimuli. Specifically, the objectives of this study were: 1) to determine the capacity of E. melanocampta adults of searching for quinoa plants using plant olfactory cues; 2) to determine the preference of E. melanocampta females for the odours derived from two varieties of quinoa: Amarilla de Marangani and Blanca de JunIn; and 3) to assess the attraction of male quinoa moths to E. melanocampta females and the host plant in olfactometric bioassays. Adults preferred quinoa plant odour sources in choice tests when distilled water was used as a control (P < 0.000 1). Females were more attracted to the Blanca de JunIn variety than to Amarilla de Marangani variety (P < 0.05). Males were more attracted to the odour derived from females than to the volatile compounds from plants (both varieties) or to the odour blend derived from plants plus females together. The level of attraction of males towards females is negatively affected by the presence of the quinoa plants. [ABSTRACT FROM AUTHOR]