​Factors Affect to Stolon Formation and Tuberization in Potato: A Review

Potato tuber formation is a complex process that is induced by a mobile signal called tuberigen. It involves several genes such as AtBMI, St 14-3-3s, StBEL, StBELL11, StBELL29, StBMI1-1, StCDF1, StCEN, StCO, StFDL1, StFT, StGA2ox1, StGA3ox2, StMSI1, StSP6A. This article focuses on important factors such as genetic factors, low temperature, high irradiation, low nitrogen, abscisic acid, chlormequat chloride, auxin, Jasmonic acid, cytokinin and paclobutrazol that induce tuber formation while ethylene, drought, low irradiation, high-temperature that reduce or inhibit tuber initiation.

Potato tuber-inducing activities of jasmonic acid and related-compounds (II)

ABSTRACT New information is being accumulated for plant-derived oxylipins, such as jasmonic acid (JA) amino acid conjugates. However, these compounds have not being examined for their activity in promoting potato tuber formation. It was found that (−)-JA had the highest activity followed cis-(−)-OPDA, (+)-4, 5-didehydroJA, cis-(+)-OPDA-l-Ile, and (−)-JA-l-Ile, -Leu, -Phe, -Val, although iso-OPDA and 3,7-didehydroJA did not exhibit activity.

Phytohormones: plant switchers in developmental and growth stages in potato

Background Potato is one of the most important food crops worldwide, contributing key nutrients to the human diet. Plant hormones act as vital switchers in the regulation of various aspects of developmental and growth stages in potato. Due to the broad impacts of hormones on many developmental processes, their role in potato growth and developmental stages has been investigated. Main body of the abstract This review presents a description of hormonal basic pathways, various interconnections between hormonal network and reciprocal relationships, and clarification of molecular events underlying potato growth. In the last decade, new findings have emerged regarding their function during sprout development, vegetative growth, tuber initiation, tuber development, and maturation in potato. Hormones can control the regulation of various aspects of growth and development in potato, either individually or in combination with other hormones. The molecular characterization of interplay between cytokinins (CKs), abscisic acid (ABA), and auxin and/or gibberellins (GAs) during tuber formation requires further undertaking. Recently, new evidences regarding the relative functions of hormones during various stages and an intricate network of several hormones controlling potato tuber formation are emerging. Although some aspects of their functions are widely covered, remarkable breaks in our knowledge and insights yet exist in the regulation of hormonal networks and their interactions during different stages of growth and various aspects of tuber formation. Short conclusion The present review focuses on the relative roles of hormones during various developmental stages with a view to recognize their mechanisms of function in potato tuber development. For better insight, relevant evidences available on hormonal interaction during tuber development in other species are also described. We predict that the present review highlights some of the conceptual developments in the interplay of hormones and their associated downstream events influencing tuber formation.

Estimating Above-Ground Biomass of Potato Using Random Forest and Optimized Hyperspectral Indices

Spectral indices rarely show consistency in estimating crop traits across growth stages; thus, it is critical to simultaneously evaluate a group of spectral variables and select the most informative spectral indices for retrieving crop traits. The objective of this study was to explore the optimal spectral predictors for above-ground biomass (AGB) by applying Random Forest (RF) on three types of spectral predictors: the full spectrum, published spectral indices (Pub-SIs), and optimized spectral indices (Opt-SIs). Canopy hyperspectral reflectance of potato plants, treated with seven nitrogen (N) rates, was obtained during the tuber formation and tuber bulking from 2015 to 2016. Twelve Pub-SIs were selected, and their spectral bands were optimized using band optimization algorithms. Results showed that the Opt-SIs were the best input variables of RF models. Compared to the best empirical model based on Opt-SIs, the Opt-SIs based RF model improved the prediction of AGB, with R2 increased by 6%, 10%, and 16% at the tuber formation, tuber bulking, and for across the two growth stages, respectively. The Opt-SIs can significantly reduce the number of input variables. The optimized Blue nitrogen index (Opt-BNI) and Modified red-edge normalized difference vegetation index (Opt-mND705) combined with an RF model showed the best performance in estimating potato AGB at the tuber formation stage (R2 = 0.88). In the tuber bulking stage, only using optimized Nitrogen planar domain index (Opt-NPDI) as the input variable of the RF model produced satisfactory accuracy in training and testing datasets, with the R2, RMSE, and RE being 0.92, 208.6 kg/ha, and 10.3%, respectively. The Opt-BNI and Double-peak nitrogen index (Opt-NDDA) coupling with an RF model explained 86% of the variations in potato AGB, with the lowest RMSE (262.9 kg/ha) and RE (14.8%) across two growth stages. This study shows that combining the Opt-SIs and RF can greatly enhance the prediction accuracy for crop AGB while significantly reduces collinearity and redundancies of spectral data.

The Improvement of Mini Tuber Production of Granola Potato Cultivar in Aeroponics System

Potato is an important food crop in both developed and developing countries and it is the fourth most important food crop after wheat, maize, and rice. Potato production in Indonesia has decreased in recent years, mainly due to the use of low quality tuber seed. The objective of this research was to determine the effect of plant materials, types of nutrients, and planting density on mini tuber formation, as well as to determine the best aeroponics conditions for mini tuber formation of Granola cultivar of potato. This research has been carried out experimentally using a Split-split Plot Design. The main plot was planting materials which consisted of plantlet and knol. The subplot was the type of nutrition media which consisted of Farran nutrition, Otazu nutrition, and AB-commercial mix. The sub-sub-plot was planting density which consisted of 50, 75, and 100 plants/m2. The research results showed that knol planted in aeroponics system on AB-commercial mix at a planting density of 75 plants/m2 resulted in the best mini-tuber production. In this study, for the first time three important factors for potato mini-tuber production have thoroughly been investigated in Indonesia. This finding will be used by Kledung Horticultural Seed Garden, Temanggung, for mass production of high-quality mini-tuber seed, which in turn will provide sufficient tuber seed for the farmer in its surrounding areas. By increasing the production of high-quality tuber seed, it is expected that it will contribute to the improvement of potato productivity and increase Indonesian potato production.

Cyperus esculentus (yellow nutsedge).

The basal bulb and tubers are the organs for vegetative propagation of C. esculentus, as well as the short-lived rhizomes, which extend for 5-30 cm, or sometimes further, before turning up and forming a further shoot and basal bulb, or a dormant tuber. The rhizomes occasionally branch, but have no viable buds at their nodes, and they decay at the end of the growing season. The number of rhiozomes is unaffected by photoperiod but tuber formation is promoted in short photoperiods (Holm et al., 1977). In the southern USA, only new shoots and basal bulbs are formed at day lengths over 14 hours, whereas all rhizomes terminate in tubers as soon as days are shorter than 14 hours (Jansen, 1971).

Propagation by Stem Cuttings of Tropaeolum pentaphyllum Lam. (Crem): An Alternative for Production of Seed Tubers

The herbaceous vine Tropaeolum pentaphyllum Lam. (Tropaeolaceae), popularly known as crem, has great potential for use, especially its tubers. However, there is still a lack of studies regarding this species. The objective of this study was to test the viability of propagation by stem cuttings for the production of T. pentaphyllum seed tubers. Two experiments were carried out in a greenhouse under controlled conditions. In both experiments, experimental design was completely randomized. In the first one, five treatments were evaluated (stem cuttings with 10, 15, 20, 25, and 30 cm) with three replicates, each one with 10 stem cuttings. In the second experiment, three treatments were evaluated (stem cuttings positions: apical, middle and basal), with four replications, each one with 10 stem cuttings. Data were submitted to analysis of variance (ANOVA) and the means were compared by Tukey’s test (p < 0.05). Stem cuttings with 15 cm length had the highest rate of tuber formation (20.0%) and produced tubers with highest mass (3.2 g). Cuttings from the middle portion of the stem had the highest rooting (52.5%) and tuber formation (45.0%) rates. Thus, cuttings with 15 cm length from the middle portion of the stem are indicated for propagation by cuttings of T. pentaphyllum. Considering the potential for the use of this species in the future, the results found in this study are very important, since the propagation by cuttings would enable the production of a large amount of seed tubers in a short period of time.

Dioscorea alata Tuber Proteome Analysis Uncovers Differentially Regulated Growth Associated Pathways of Tuber Development

During its life cycle Dioscorea tuber undergoes multiple morphological and biochemical changes. To gain a better understanding of the metabolic changes associated with the tuber growth a stage specific gel free proteome analysis of four distinct morphological stages namely germinating tuber (S1), degrading tuber (S2), new tuber formation (S3) and tuber maturation (S4) was done and validated by principal component analysis (PCA). A comprehensive data set identifying 78.2% of the total 3,681 proteins was generated. PANTHER and KEGG MAPPER revealed both expected (carbohydrate metabolism and redox regulation) and novel biological processes (transcription factors and hormonal regulation) characteristic for each developmental stage. Higher abundance of the enzymes of ascorbate-glutathione cycle (ASC-GSH) and carbohydrate metabolism was detected during tuber germination (S1) and tuber formation stages (S3) in comparison with the mature tuber. The presence of ethylene biosynthesis components during tuber formation hints towards its probable role in the post- harvest shelf life. The data set comprehensively describes the proteome of Dioscorea tuber and provides growth specific markers for tuber germination (APx, MDHAR, invertase) and tuber formation (sucrose synthase) which were validated by enzyme activity assays and western blotting. The study provides information that may influence the direction of research for improving the productivity of this under-utilized neglected crop.