Agronomic and Economic Interactions between Sidedressed Nitrogen and Potassium Fertilizations on Atlantic Potato

Abstract Nitrogen (N) and potassium (K) in potato crop planting synergistically increase tuber yield, but there are no studies on this interaction in sidedressing. In two experiments with 'Atlantic' potato combinations of four N rates (0, 50, 100, and 150 kg ha-1) with four K2O rates (0, 100, 200, and 300 kg ha-1) were applied in sidedressing in a 4×4 factorial scheme with three replications in a completely randomized design. Adjacent commercial fields were sampled to economic comparisons with experimental results. Significant interaction between N and K sidedressing rates with tuber yields increase also was confirmed and classified as Liebig-synergism. Compared to the isolated N and K applications in sidedressing, joint N and K fertilizations, respectively, increases by 11% and 48% marketable tuber yields in the summer-fall experiment, and 12% and 7% in the spring experiment. Joint N and K applications as sidedressing was more profitable than planting fertilization, mainly at higher N and K rates. The response of specific gravity of 'Atlantic' potato tubers to the N and K sidedressing rates was mediated by interactions between edaphoclimatic conditions and inputs of N and K. The combined application of N and K sidedressing rates increased specific gravity in the summer-fall experiment, but had a negative effect in the spring experiment. Therefore, our results provide strong evidence that the fertilization management for potato crop in Brazil can be modified by applying higher amounts of N and K in sidedressing to match nutritional needs of the crop.

Purification of a novel chitin-binding lectin with antimicrobial and antibiofilm activities from a Bangladeshi cultivar of potato (Solanum tuberosum).

A new chitin-binding lectin was purified from a Bangladeshi cultivar ‘Deshi’ of potato (Solanum tuberosum L.) through anion-exchange and affinity chromatographies using a chitin column. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed the molecular mass of the lectin as 20,000 Daltons. This molecular mass was almost half of the molecular masses of chitin-binding lectins derived from other potatoes. The lectin showed both bactericidal and growth-inhibiting activities against Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli, Salmonella enteritidis and Shigella boydii) pathogenic bacteria. It also showed antifungal activity against Rhizopus spp., Penicillium spp. and Aspergillus niger. Biofilm produced by the bacterium Pseudomonas aeruginosa was dose-dependently reduced by 5-20% in 24 h after administration of the lectin, which was attributed to the glycan-binding property of the lectin having affinity to GlcNAc polymers. It was the first observation that any potato lectin prevented biofilm formation by P. aeruginosa and, therefore, could have possible applications in clinical microbiology and biomedical science.

Analysis of genetic and epigenetic variation in in vitro propagated potato somatic hybrid by AFLP and MSAP marker

Background: Genetic and epigenetic changes (DNA methylation) were examined in the tissue-culture propagated interspecific potato somatic hybrids between dihaploid Solanum tuberosum and S. pinnatisectum. Amplified fragment length polymorphism (AFLP) and methylation-sensitive amplified polymorphism (MSAP) were applied to detect the genetic and epigenetic changes, respectively in the somatic hybrids mother plants (1st cycle) and their regenerants (30th cycles sub-cultured). Results: To detect genetic changes, eight AFLP primer combinations yielded a total of 329 scorable bands of which 49 bands were polymorphic in both mother plants and regenerants. None of the scorable bands were observed in term of loss of original band of mother plant or gain of novel band in their regenerants. AFLP profiles and their cluster analysis based on the Jaccard’s similarity coefficient revealed 100% genetic similarity among the mother plant and their regenerants. On the other hand, to analyze epigenetic changes, eight MSAP primer pair combinations detected a few DNA methylation patterns in the mother plants (0 to 3.4%) and their regenerants (3.2 to 8.5%). Out of total 2320 MSAP sites in the mother plants, 2287 (98.6%) unmethylated, 21 (0.9%) fully methylated and 12 (0.5%) hemi-methylated, and out of total 2494 MSAP sites in their regenerants, 2357 (94.5%) unmethylated, 79 (3.1%) fully methylated and 58 (2.3%) hemi-methylated sites were amplified. Conclusion: The study concluded that no genetic variations were observed among the somatic hybrids mother plants and their regenerants by eight AFLP markers. However, minimum epigenetic variations among the samples were detected ranged from 0 to 3.4% (mother plants) and 3.2 to 8.5% (regenerants) during the tissue culture process.

Qualidade de processamento de tubérculos de batata produzidos sob diferentes disponibilidades de nitrogênio / Potato processing quality of tubers grown under different nitrogen availabilities

O objetivo do trabalho foi determinar o teor de matéria seca e a coloração de chips de batata da cultivar Asterix produzidos sob cinco níveis de nitrogênio. O plantio foi feito em 02/09/2003, na UFSM, em sacolas com 4,4dm de substrato comercial. Os tratamentos foram constituídos por cinco soluções nutritivas com doses de N de 5,0 (T1), 8,3 (T2), 11,3 (T3), 14,3 (T4) e 16,3mmol L-1 (T5). Os tubérculos foram colhidos em 17/12/2003, aos 104 dias após o plantio, e após 15 dias na temperatura de 20ºC foram determinados o teor de matéria seca e a coloração dos chips. O teor de matéria seca dos tubérculos aumentou da primeira até a terceira dose, decrescendo a seguir segundo um modelo polinomial. Os valores foram de 19,5; 20,5; 20,8; 18,6 e 18,4g 100g-1 nas doses de T1 a T5, respectivamente. Somente os tubérculos produzidos com as doses T2 e T3 atingiriam o teor mínimo de matéria seca preconizado pela literatura, que é de 20g 100g-1. Não houve relação entre a coloração dos chips e as doses de N fornecidas. Concluiu-se que o N pode reduzir o teor de matéria seca dos tubérculos e que critérios específicos de manejo da adubação nitrogenada devem ser observados para a produção de tubérculos destinados ao processamento industrial.

Filocrono em diferentes densidades de plantas de batata / Phyllochron at different plant densities in potato

O conceito do filocrono, ou seja, o intervalo de tempo necessário para a emissão de duas folhas consecutivas, pode ser usado para simular o aparecimento de folhas em plantas. O número de folhas, além de afetar o índice de área foliar da planta, é considerado uma excelente medida de tempo fisiológico. O objetivo do trabalho foi estimar o filocrono em batata cultivada num sistema hidropônico com substrato em diferentes densidades de plantas. O experimento foi conduzido em ambiente protegido, no Departamento de Fitotecnia da UFSM, RS, no período de 03/09/2004 a 26/10/2004. O delineamento experimental foi o inteiramente casualizado, com três repetições. Os tratamentos foram os espaçamentos de 5x5, 10x10, 15x15 e 20x20cm entre covas. Os valores de filocrono para cada densidade foram relacionados com o número de covas m-2 e de hastes m-2. Os valores de filocrono estimados variaram em função da densidade de plantas. As maiores densidades promoveram aumentos no filocrono, indicando que a densidade de plantas afeta a velocidade de surgimento de folhas em batata, e esta resposta deve ser contemplada em modelos de simulação do número de folhas nesta cultura.

In vitro microtuberization in potato (Solanum tuberosum L.) cultivars.

Mechanism of microtuberization in three elite cultivars kufri badhsha (KB), kufri chandramukhi (KCM) and kufri jawahar (KJ) of potato was studied. Sprouts of all the three cultivars were used to obtain in vitro shoot cultures. MS medium supplemented with chlorocholine chloride was found to be most suitable for all the cultivars. Maximum tuberization was obtained under incubation conditions of continuous darkness at 20 degrees +/- 1 degrees C. The highest number of micro-tubers per plant basis was produced under continuous darkness and KCM recorded the highest yield of micro-tubers and was found significantly superior to KJ and KB.

Monoxenic in vitro production and colonization potential of AM fungus Glomus intraradices.

The paper reports the establishment of mycorrhizal infection of a non-mycorrhizal Ri-T-DNA transformed carrot root when co-cultured with a surface sterilized sweet potato root segment colonized by arbuscular mycorrhizal (AM) fungus G. intraradices on minimal M medium. Extensive fungal hyphal emergence from each cut end of the mycorrhizal sweet potato root piece was observed in one week old cultures. These hyphae caused infection on contacting the transformed-carrot- root segment and produced many hyphae and spores both inside and outside the zone of the root after 6 week of growth. Axenically produced fungal propagules proliferated on the surface of fresh minimal M medium when sub-cultured without any root segment. On repeated sub-culturing, these propagules did not lose their ability to grow and produced many juvenile small spore-like vesicles during the non-symbiotic phase. Although these spores were morphologically and anatomically similar to their soil borne counter parts, they were much smaller. When placed in the vicinity of a fresh hairy root on the minimal medium or a Sudan grass seedling in sand culture, the axenically produced AM fungal propagules caused root infection, but the infection characteristics were significantly different to the original culture in terms of shape (spherical vs oval) and size (20 microm vs 45 microm) of the intraradical vesicles, and absence of 'H' branches. Sudan grass seedlings inoculated with the axenically cultured fungus showed significantly (P < 0.05) higher dry weights plant'. When compared to the plants inoculated with sand cultures, the growth parameters and the percentage infection were not significantly different. However, when both sources of inocula were used together, a synergistic effect on plant growth as well as root infection was observed.

Biochemical changes in peroxidase, polyphenol oxidase, superoxide diemutase and catalase activities of potato rat different stages of development

Four enzymes peroxidase, polyphenal oxidase superaxide dismutase and catalase were studied in potato tuber cultivar 'ALPHA' at different stages of development by using PAGE PoroPAGE and PAGIF electrophoresis. The activities of the four enzymes are positively related to each other through tuberization and maturation. In contrast to other plants which lime been reported So contain multiple forms of catalase, only one fourm of this enzyme was revealed in potato sap Peroxidase was detected as 9 bands after PAGE and 10 bands after PoroPAGE with MW between 20-134 KDa Superoxide dismutase was detected as 10 bands after PoroPAGE and 6 bands after PAGE with MW between 10-120 KDa. Our results showed that the four enzymes have been involved in growth and development