Influence of Harvest Periods on Cassava (Manihot esculenta Crantz) Agronomic Traits and Physiological Response to Post-Harvest Physiological Deterioration

Cassava (Manihot esculenta Crantz) is the third largest source of calories in tropical countries and the sixth most important food crop in the World. However, the short shelf life of its storage roots after harvest due to a rapid post-harvest physiological deterioration (PPD) makes the roots to be considered as a risky product to market. The objectives of this work were to investigate the influence of two harvest periods on cassava agronomic parameters and their physiological response to PPD. Three cassava cultivars 96/1414, I070593 and LMR were selected for the experiment and harvested at 10 and 12 months after planting (MAP). The response to PPD was assessed during storage at 0, 3, 8 and 15 days after harvest (DAH). Total proteins content, soluble sugars and starch, total polyphenols compounds, polyphenoloxidase and peroxidase activities were recorded during storage. Results showed large variation among the parameters at the two harvest periods across the cultivars. High number of tubers was recorded in all the cultivars at 12 MAP and a significant increase in storage roots length was observed in 96/1414 and LMR from 10 MAP to 12 MAP (25 ± 5.1 to 41.3 ± 5.9 and 22.6 ± 3.3 to 27.9 ± 4.8) respectively. A reduction of about 49% of tubers weight was observed in I070593 from 10 to 12 MAP while an increase of about 36% and 11% were recorded in LMR and 96/1414 respectively. Tubers from I070593 showed less susceptibility to PPD when harvested at 10 MAP compared to those from LMR and 96/1414 where less susceptibility to PPD were recorded at 12 MAP. An increase in soluble sugars content, total proteins content and peroxidase activity subsequently to a decrease in starch content were recorded during storage from 8 to 15 days after harvest especially at 10 MAP in I070593 and at 12 MAP in LMR and 96/1414. High content of total phenolic compounds and less activity of polyphenol oxidase were correlated to PPD susceptibility. This work opens a new insight issue of the consideration of the appropriate harvest time of the cultivars as a tool to better control the onset of postharvest physiological deterioration.

Study on chemical composition of Viscum coloratum and its HPLC fingerprint in different harvest periods

The purpose of this study was to evaluate the similarity of chemical profile of Viscum loloratum harvested in different months using high performance liquid chromatography(HPLC)fingerprint and multivariate statistical analysis,and to determine the optimal harvest time of Viscum coloratum.8 compounds were isolated from Viscum coloratum by a variety of isolation techniques,3 of which were isolated from the genus Viscum L.for the first time.The fingerprint of Viscum coloratum was established by HPLC,and 16 common peaks were obtained,4 of which were identified by comparison with the reference substances.Results showed that the Viscum coloratum harvested in 6 months could be roughly divided into three groups based on the chemical profiles,and the Viscum coloratum harvested in January had higher levels of the marked compounds.The HPLC fingerprint objectively reveals the characteristics of Viscum coloratum harvested in different months,which can be used to evaluate and control the quality of Viscum coloratum harvested in different months.

Effects of Different Harvest Periods on Seed Quality of Alpinia oxyphylla Miq.

[Objectives] To clarify the appropriate harvest period of Alpinia oxyphylla Miq. seed and improve the quality of seeds. [Methods] In this experiment,the basic parameters and germination characteristics of A. oxyphylla Miq. seeds during different harvest periods were analyzed and compared. [Results] The results showed that the A. oxyphylla Miq. fruit picking period was closely related to the seed quality,and the seed maturity was highest 100 d after the flowering of A. oxyphylla Miq.,that is,the A. oxyphylla Miq. fruit skin turned from green to yellow( yellow-green),the peel had a small number of brown spots,it was spicy enough,the fruit dry/fresh weight ratio was greater than0. 34,the seed thousand kernel weight reached 11 g or more,and the dried seed moisture content was 13. 01%. Using the TTC method,the seed viability index was determined to be 85%,and in this case,it was the best time of harvesting seed. The water permeability of A. oxyphylla Miq. seed was poor,and the seed imbibition and water absorption time was long,about 72 h. The maximum water absorption rate was about23. 71% at the imbibition and water absorption stage,and it was inferred that the A. oxyphylla Miq. seeds were hard seeds. The germination time of A. oxyphylla Miq. seeds was long,the mature A. oxyphylla Miq. seeds began to germinate on the 12 th d,and the germination rate reached 75. 56% on the 50 th d. [Conclusions] This study determined the optimum harvest period of A. oxyphylla Miq. seeds,clarified the biological characteristics of slow seed water absorption and long germination cycle,and concluded that the seed coat was the main factor leading to slow seed water absorption and long seed germination cycle.

FAA Composition and Content Variation in Different Pyropia yezoensis Cultivar in Harvest Period

The contents of 16 kinds of free amino acids （FAAs） in 7 Pyropia yezoensis cultivars were determined by pre-column derivatization high performance liquid chromatographyin early, middle and late harvest period.The results showed that the total FAA content ranged from 48.71 to 62.05 mg/g among the 7 test ma- terials. Among the 16 kinds of FAAs, Ala, Arg, Glu and Asp, four kinds of flavor amino acids, showed the highest contents, and their total content ranged from 36.05 to 53.96 mg/g, accounting for 69.11%-86.47% of the total FAA content. The total contents of flavor amino acids and FAAs all reached the peaks in all the test ma- terials, except the control cultivar, at middle harvest period. The essential amino acid content was trended to be increased in all the test materials with the extended harvest period, and it reached the peak at the late harvest period. Sutong showed the highest flavor amino acid content and FAAs content, followed by Y-H002, Suyan and Sulian, while the control cultivar showed the lowest contents.

Quality Change in the Course of Fruit Development of Specific Cucumber Cultivars

[Objective] To study optimal harvest period of Zhongnong No.19 and Zhongnong No.29. [Method] The optimal harvest periods of the two cucumber culti- vars, Zhongnong No.19 and Zhongnong No.29, were investigated through analyzing the changes of fruit appearance （vertical diameter, transverse diameter） and quality （contents of soluble protein, soluble saccharide, and vitamin C） in the entire course of fruit growth. [Result] Zhongnong No.19 and Zhongnong No.29 grew at the fastest rate during the 5-10 d of life. The longitudinal and transverse diameter increased with time. The protein and vitamin C content of cucumber was： Zhongnong No.19 reached the highest in 8d, then decreased and became stable, while Zhongnong No.29 reached the highest in 8d, then decreased and increased again. Soluble sac- charide content of Zhongnong No.19 first rose then fell and rose again; Zhongnong No.29 had two peaks. [Conclusion] Based on the physiological and morphological index, the eighth day after blooming was the optimal harvest day for Zhongnong No.19 and Zhongnong No.29 fresh fruits.

Mapping of Quantitative Trait Loci （QTLs） Controlling Cherry and Green Bean Characters in the Robusta Coffee （Coffea canephora Pierre）

In coffee breeding practice, two quantitative traits, namely cherry and green bean characters are the important phenotypic selection index. The synchronous of cherry maturation, size, weight and shape of green bean are desirable traits for the future breeding. In order to increase the breeding efficiency, a set of quantitative trait loci （QTLs） analysis controlling these traits was carried out. The QTL analysis was performanced in cross pollinated population of Coffea canephora using single nucleotide polymorphisms （SNPs） and simple sequence repeats （SSRs） markers. Totally 12 QTLs determined desirable cherry and green bean traits were identified on 9 linkage groups （LG）, where these QTLs mapped forming clusters in 11 different chromosomal regions. The desirable traits which can be detected by their QTLs are synchronous of cherry maturation （LG B and LG G）, cherry size （LG A, LG F and LG G）, bean shape （LG B, LG D and LG J）, bean weight （LG H）, bean size （LG A and LG E） and cherry-bean size （LG K） The gene action of these QTLs was dominance or an interaction of alleles （epistasis between alleles at the studied locus） effect. The yielded linkage map and the detected QTL can provide a tool for further genetic analysis of two traits and be potential for maker-assisted selection in C. canephora breeding.

COMPLEXITY ANALYSIS AND COMPUTATION OF THE OPTIMAL HARVESTING FOR ONE-SPECIES POPULATION RESOURCES

The exploitation of renewable resources creates many complex problems for culture, ecology and economics as well. Ascertaining the essentials behind the coraplex problems is very important, in this paper, we mainly study various complex relations appearing in the optimal exploitation process for renewable resources. First, we derive a sufficient condition on the existence of optimal harvesting policies for one-species population resources. Then we present every possible optimal harvesting pattern for such a modeh On the basis of this, we give a computing formula for estimating the optimal harvesting period, optimal transitional period, and optimal recruitment period. The main difference with respect to the previous works in literature is that our optimal harvesting policy is a piece-wise continuous function of time t, at the piecewise point to, which is called switching time. At the switching time we switch the harvesting rate from h to some transitional control u,, then to 0. Clearly this kind of harvesting policy is easier to carry out than those by others, provided that there exists a managing department which can highly supervise the resources.

Comprehensive evaluation of Korla fragrant pears and optimization of plucking time during the harvest period

To optimize the harvest of Korla fragrant pears and to provide a theoretical basis for post-harvest processing,a total of 26 basic indices of Korla fragrant pears,including their morphology,quality,and softening age,were investigated.The harvest period ranged from August 22nd to October 6th,samples were collected every 5 d(totally 10 plucking days,indicated as H1-H10).The results indicated that changes in pectin content were the main causes of softening in fragrant pears.The scavenging of free radicals mainly occurred because of the collaborative effects of superoxide dismutase(SOD)and catalase(CAT).In the harvest periods H1-H3,the hardness,titratable acid(TA),chlorophyll content,density,and diameter of the stone cells,as well as the cellulose and hemicellulose content of the Korla fragrant pears were at their highest.During the periods H7-H10,the single-fruit weight,fruit horizontal and vertical diameter,color coordinates L,a*,b*,soluble-solids content(SSC),SOD activity,CAT activity,and water-soluble pectin were higher than in the other plucking periods.The highest vitamin C(VC)content and moderate values for a variety of indicators were observed during H3-H7.Variations in the Korla fragrant pears during H1-H3 mainly manifested through changes in softening-related parameters.During H3-H10,changes in the softening-related,aging-related,color-related,and quality indices had a dominant role.On this basis,some suggestions for the post-harvest processing of fragrant pears have been proposed.Fruit,during H1-H3,are suitable for transportation and storage;during H7-H10 are suitable for fresh-eating and further processing;and during H3-H7,exhibited moderate values for a variety of indicators and had the highest commercial value.This research provides a systematic evaluation of the characteristics of mature Korla fragrant pears during the harvest period and can form the basis for fruit quality control and processing of Korla fragrant pears.

Study on the dynamic variation of the secondary metabolites in Viscum coloratum using targeted metabolomics

Viscum coloratum(Kom.)Nakai is a well-known medicinal plant.However,the optimal harvest time for V.coloratum is unknown.Few studies were performed to analyze compound variation during storage and to improve post-harvest quality control.Our study aimed to comprehensively evaluate the quality of V.coloratum in different growth stages,and determine the dynamic variation of metabolites.Ultra-performance liquid chromatography tandem mass spectrometry was used to quantify 29 compounds in V.coloratum harvested in six growth periods,and the associated biosynthetic pathways were explored.The accumulation of different types of compounds were analyzed based on their synthesis pathways.Grey relational analysis was used to evaluate the quality of v.coloratum across different months.The compound variation during storage was analyzed by a high-temperature high-humidity accelerated test.The results showed that the quality of V.coloratum was the hightest in March,followed by November,and became the lowest in July.During storage,compounds in downstream steps of the biosynthesis pathway were first degraded to produce the upstream compounds and some low-molecular-weight organic acids,leading to an increase followed by a decrease in the content of some compounds,and resulted in a large gap during the degradation time course among different compounds.Due to the rapid rate and large degree of degradation,five compounds were tentatively designated as“early warning components”for quality control.This report provides reference for better understanding the biosynthesis and degradation of metabolites in V.coloratum and lays a theoretical foundation for rational application of V.coloratum and better quality control of V.coloratum during storage.