Richard Bustos’s research while affiliated with University of Tarapacá and other places

Maize has been one of the most important crops in the foothills of the Arica and Parinacota region. Its current management and development, based on traditionalpractices, without significant interventions and with the least negative impact on the environment, evidence the conservation of very important agricultural germplasm by local farmers, custodians of their seeds and those who have incorporated this crop as an essential part of their life, through its daily use and in activities typical of the culture of northern Chile.

The productive diversity of the Lluta valley, located in the north of Chile, is conditioned by the high salinity and excess of boron present in the soil and irrigation water that can affect the physiological behavior of crops, requiring the use of tolerant hybrids or of local varieties adapted to this condition. To take advantage of the potential of local germplasms, regarding their tolerance to salt stress, a participatory plant breeding work has been carried out using the local parent "Poncho Negro" (TP 1 ) and two commercial tomato hybrids (TP 2 and TP 3 ), generating new lines that could be potential altern^tives to the use of commercial hybrids due to their greater tolerance to the stress present in this valley. In this work, the behavior of these tomato lines (generation F3) and their parents was evaluated in the soil and water conditions of the Lluta valley, confirming the high tolerance of the TP 1 parent to this type of abiotic stress. According to the evaluated parameters, T 7 would be one of the lines that could best develop in this valley, maintaining the salinity tolerance characteristics of its parent TP 1 , becoming an alternative for this saline valley.

The current study presents the way in which ions are distributed in an adult maize plant after flowering, and as the pressure of permanent ion stress throughout approximately six months; including all the phenological periods. The research was conducted under field conditions with the climatic characteristics of an arid or hyper-arid zone. Maize is a sensitive crop regarding the salinity of soil and water, but "lluteño" maize has a higher degree of tolerance to salinity, excess of boron (B) and other ions, this suggests that the distribution plays an important role in the tolerance mechanisms of this ecotype. The variety accumulates twice as much sodium (Na+) in the root than in the leaf, and 25 times of B more in the leaf than in the root; calcium (Ca2+), magnesium (Mg2+ and potassium (K+) were also significantly accumulated in the leaf. High concentrations of B, Ca2+, and Mg2+ were found in the thick root and K+ in the fine roots. Sodium accumulated similarly in thick and fine roots, suggesting a very active mechanism of Na+ accumulation in roots, independent of their thickness or age.

Beetroot (Beta vulgaris L.) is recognized for its composition of bioactive molecules such as betalaine, which makes its consumption significantly beneficial for human health. Its synthesis would be influenced by factors such as salinity, one of the main stresses that characterize the coastal desert valley of Lluta, located in the northern of Chile, added to these characteristics is the excess of boron that limits agricultural diversification of the valley to crops tolerant to this environmental condition. In the present study, the effect of salinity and seasonal temperature on the synthesis of betalaine (betacyanin and betaxanthin) in the Detroit (T0) and Larka (T1) varieties were evaluated, there are significant statistical differences in the synthesis of both biomolecules amongst varieties, not so between growing seasons. The results, as regards the synthesis and content of betalaine, show the feasibility of incorporating Larka as a productive alternative for the Lluta Valley, being possible to allocate its production to fresh consumption or as a raw material for the industry dedicated to the extraction of natural pigments.

The "PonchoNegro" tomato was introduced to the Valley of Lluta more than 40years ago from Cochabamba (Bolivia). Recognized for its special features, she had a promising boom, however, because of its short postharvest life was displaced by new hybrid varieties introduced to the regional market. At his impending loss, it has been proposed to work on his recovery and revaluation, seeking to strengthen its development, while, keep it as a feasible plant genetic resource to use as diversification and incorporate a group of crops that tolerate the impending climate change and its effects on crop production in arid and semi-arid areas of the different regions of the world.

Micromorphological and anatomical characteristics of the leaves of Zea mays L. amylacea were analyzed using digital images obtained from SEM. Concentrations of 100 mM NaCl (low salinity, L) or 430 mM NaCl (high salinity, H) and/or an excess of B supplied as boric acid to obtain 20 (334 μM) and 40 (668 μM) mg B kg-1 were added to the nutrient solution for 20 days. Our results complement other studies of the ecotype amylacea and confirm the high degree of tolerance to salinity and excess boron it shows, especially in the role of xylem vessels in the entry and transport of water and ions and their relation to the regulation of the stomata.

It is known that exogenous salicylic acid (SA) plays a role in the response of plants to salt and osmotic stresses. In recent years, SA has been shown to increase the concentrations of organic solutes for osmoregulation in plants subjected to salt stress. Therefore an experiment was conducted to investigate the impact of exogenous SA on the tissue morphology of lluteño maize. The treatment consisted of salt and SA (0.1 mM). Salt stress negatively affected leaf anatomy by showed a positive effect of SA on the composition of structures such as xylem vessels, Kranz anatomy, mesophyll cells, epidermal tissues, leaf blades and chloroplast development. It also increased the number of stomata per unit area. Finally, the presence of salicylic acid in saline conditions has beneficial effects on the morphology of lluteño maize, likely contributing to the tolerance to salinity.

It is known that exogenous salicylic acid (SA) plays a role in the response of plants to salt and osmotic stresses. In recent years, SA has been shown to increase the concentrations of organic solutes for osmoregulation in plants subjected to salt stress. Therefore an experiment was conducted to investigate the impact of exogenous SA on the tissue morphology of lluteño maize. The treatment consisted of salt and SA (0.1 mM). Salt stress negatively affected leaf anatomy by showed a positive effect of SA on the composition of structures such as xylem vessels, Kranz anatomy, mesophyll cells, epidermal tissues, leaf blades and chloroplast development. It also increased the number of stomata per unit area. Finally, the presence of salicylic acid in saline conditions has beneficial effects on the morphology of lluteño maize, likely contributing to the tolerance to salinity.

We analyzed the mitigating effect of NO3 - and salicylic acid (SA) on the detrimental effects of salt stress by studying the water status of plants of maize grown in Hoagland's medium with NaCl 100 mM as the saline component, to which SA and NO3 - were added in different concentrations as mitigating agents. We evaluated water potential Ψw, osmotic potential Ψs, relative water content (RWC), turgor potential (Ψp ), and the osmotic adjustment (OA) of leaves and roots. SA 0.5 mM mitigated the effects of salinity by increasing the Ψs of the leaf, the Ψsof theroot, the Ψpof the leaf, RWC and OA of the leaf; while NO3 was only effective in combination with SA, mitigating the effects of salinity by increasing RWC and OA. However, the interaction SA-NO3 reduced leaf Ψw and Ψs of leaves and roots. Mtigation of salt stress was also detected by a positive effect on plant growth. The greatest effect on growth was produced by the NO3 treatments and SA 0.5 mM combined with NO3.

and L. Cardemil. 2010. Mitigating effect of salicylic acid and nitrate on water relations and osmotic adjustment in maize, cv. Lluteño exposed to salinity. Cien. Inv. Agr. 37(3): 71-81. We analyzed the mitigating effect of NO 3 -and salicylic acid (SA) on the detrimental effects of salt stress by studying the water status of plants of maize grown in Hoagland´s medium with NaCl 100 mM as the saline component, to which SA and NO 3 -were added in different concentrations as mitigating agents. We evaluated water potential (Ψ w), osmotic potential (Ψ s), relative water content (RWC), turgor potential (Ψ p), and the osmotic adjustment (OA) of leaves and roots. SA 0.5 mM mitigated the effects of salinity by increasing the Ψ w of the leaf, the Ψ s of the root, the Ψ p of the leaf, RWC and OA of the leaf; while NO 3 -was only effective in combination with SA, mitigating the effects of salinity by increasing RWC and OA. However, the interaction SA-NO 3 -reduced leaf Ψ w and Ψ s of leaves and roots. Mitigation of salt stress was also detected by a positive effect on plant growth. The greatest effect on growth was produced by the NO 3 -treatments and SA 0.5 mM combined with NO 3 -.