Browsing by Subject "Andean lupin"

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  • Zou, Ling (Helsingfors universitet, 2009)
    Andean lupin (Lupinus mutabilis Sweet) is a potential oilseed crop, with a very high protein content (40–45%) and 15–20% oil content. It is valued as an alternative protein source for both human and animal consumption, and like several other lupin species, has a potential role in phytoremediation. Previous experience in central and southern Europe has shown the crop to have low and unstable yields with high sensitivity to heat and drought during the grain–filling stage. The species may therefore be more suitable for cool–temperate climates, as it comes from similar altitudes and latitudes as potato. Therefore, an experiment was set out to quantify the responses of Andean lupin to heat stress, using both gradually and suddenly rising temperatures during grain filling. In preliminary tests 60 accessions from 4 germplasm banks were screened for time to flowering and daylength sensitivity. For this experiment, 3 accessions were chosen, 478435, 457972, 457977, with vegetative phase durations of 44, 53, 64 days from sowing to first flower, respectively. Forty two plants of each accession were sown and reduced to 30 on the basis of uniformity. Plants were grown in a glasshouse with 22 °C, 18 h days and 18 °C, 6 h nights until about 25 days after flowering. Ten plants of each accession were subjected to one of the following treatments: control (continuing in the same glasshouse conditions), sudden heat stress (transferred to a growth chamber and subjected to 38 °C from 11:00 to 15:00) or gradual heat stress (transferred to a growth chamber and subjected to temperature increases of 4 °C day temperature and 2 °C night temperature, with the final two days at 38 °C from 11:00 to 15:00). The plants were returned to the glasshouse and when mature, the seeds were harvested and pooled into 3 replicates per accession and treatment for quality analysis. Seed protein, oil, soluble sugar, ash and moisture content were determined. Data were calculated on the basis of percentage of overall seed mass and also on a milligrams per seed basis in order to reflect the seed physiology at grain–filling stage. Sudden heat stress had greater effects on seed composition than gradual heat stress. When compared with control, sudden heat stress resulted in more loss of every component than gradual heat stress, on a per–seed basis, in all 3 accessions and the responses of the accessions to the sudden stress were not statistically different. Under sudden heat stress, mean seed weight declined by 70%, protein content by 70%, oil content by 85%, ash content by 50%, and soluble sugar content by 75%. The accessions responded differently, however, to the gradual heat stress. Accession 478435 experienced significantly greater reduction in seed weight, protein and ash content than accessions 457972 and 457977. Oil content per seed and soluble sugar content per seed were also lower in 478435 than in the other two cultivars, but the difference was not significant. On the flour basis, sudden heat stress increased ash content and decreased oil content and soluble sugar content significantly in all accessions. Accession 478435 had highest value in ash content at significant level. Under gradual stress, protein and ash content were increased while oil mass and soluble sugar mass were decreased. 478435 had significantly higher protein mass and ash mass in flour with respectively 57% and 5.1%, 457977 had significantly higher soluble sugar content with 112 mg/g. The results showed that heat stress can have a significant effect on the quantity and quality of seed yield in Andean lupin. While all tested accessions were severely susceptible to sudden heat stress, gradual stress identified differences between accessions, with one being much more susceptible than the other two. The most susceptible accession was the earliest to flower. Gradual heat stress allows better resolution than sudden heat stress when screening germplasm for heat tolerance.
  • Lizarazo Torres, Clara Isabel (Helsingfors universitet, 2010)
    Drought is one of the most important abiotic stresses that causes significant reductions in crop yield, and thus hinders the food security of the growing world population. In consequence, it is urgent to select crops able to resist drought, maintain high yield and have a good nutritive content. The purpose of this project was to evaluate the responses of different accessions of Andean lupin to drought stress, and identify if there are significant differences in their physiological responses. To identify germplasm for further investigation, thirty accessions of Lupinus mutabilis Sweet. and one accession of L. albococcineus Hort. were screened in two sets, A of 15 and B of 16 accessions. From these sets, four lines were chosen on the basis of extreme values in the measurements, and this set of four was investigated in depth (set C). In all experiments, ten seeds of each chosen accession were sown in pots and grown in a glasshouse with 22°C, 18 h days and 18°C, 6 h nights, and were well watered until day 50 after planting. The pots were arranged in a randomized complete block design. The eight most uniform plants were chosen, and four were exposed to water stress while watering of the other four was continued. Water stress consisted of controlled water loss from the soil, 20% water holding capacity at 2% per day over 9 days, so the soil reached 2% moisture content and was held at this level for 2 days more. In all experiments, leaf temperature, stomatal conductance, relative water content, water potential, ion membrane leakage, and shoot dry weight were measured and transpiration efficiency was calculated. In set C, carbon isotope discrimination, root length, root dry matter, proline content and soluble sugar content were also determined. The analysis of set A and B revealed significant differences between treatments for all the parameters measured, except for relative water content, and there were also differences amongst accessions in certain parameters. PI 457972 and PI 457981 were selected for further investigation because of their low stomatal conductance under water stress conditions and low water use, and PI 510572 was selected as sensitive to drought stress due to its high water use, ion membrane leakage and water potential under water stress conditions. In addition AC 2792 (L. albococcineus) was selected due to its low stomatal conductance and water use, and high leaf temperature under water stress conditions. In the final experiment, PI 457981 and PI 457972 appeared to avoid drought through appropriate stomatal characteristics. PI 457981 showed low stomatal conductance, high leaf temperature and also high root length, similarly, accession PI 457972 showed low water potential, low stomatal conductance, low carbon isotope discrimination and accumulation of soluble sugars. Accession PI 510572 contrasted for these stomatal traits, but interestingly it showed low membrane ion leakage, high proline content and soluble sugars content, suggesting that it was capable of drought tolerance by osmotic adjustment. Finally, accession AC2792 showed low water use, low water potential and low carbon isotope discrimination. This survey thus identified accessions of Andean lupin that were able to avoid drought stress through stomatal traits and root traits, and other that were able to tolerate drought through the accumulation of osmotically active substances. Thus, there are good prospects for breeding of Andean lupin to improve its drought resistance.