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  • Yujie LI, Ning WANG, Yayi MENG, Xue HAI, Huixian XING, Hongjuan LIU, Chunyu SHI, Chengcheng SI
    Chinese Journal of Tropical Crops. 2024, 45(2): 362-369.

    Five sweet potato cultivars with significant differences in germination, Jixu 23, Yanshu 25, Red Banana, Taizhong No. 6 and Xinxiang, were used as the test materials. During the storage period, samples were taken regularly to analyze the changes of endogenous hormones and carbohydrate metabolism in the storage roots. Storage roots after storage were planted for seedlings in small arch sheds and investigated. The results showed that Jixu 23, Yanshu 25 and Red Banana germinated earlier, and the number of seedlings picked was significantly more than that of Taizhong 6 and Xinxiang. At the end of storage and before seeding, the starch content and amylopectin content of storage roots in Jixu 23, Yanshu 25 and Red Banana were significantly higher than those of Taizhong No. 6 and Xinxiang, Jixu 23, Yanshu 25 and Red Banana. Higher content of amylopectin and amylopectin was mainly due to the smaller decrease during storage. The total amylase and α-amylase activity of storage roots in Jixu 23, Yanshu 25 and Red Banana were significantly higher than that of Taizhong No. 6 and Xinxiang, and the α-amylase activity of storage roots in Jixu 23, Yanshu 25 and Red Banana were higher than that of Jixu 23, Yanshu 25 and Red Banana. This is mainly due to the larger increase during storage. At the end of storage and before seeding, compared with Taizhong No. 6 and Xinxiang, Jixu 23, Yanshu 25 and Red Banana had higher GA content, lower IAA content, and higher GA/ABA and ZR/IAA of storage roots. That is, at the end of storage and before seeding, high starch and amylopectin content, high α-amylase activity, high endogenous GA content, and low IAA content in storage roots are physiological indicators of good germination.

  • Shixiang XIAO, Weiyan XUAN, Dou FENG
    Chinese Journal of Tropical Crops. 2024, 45(2): 296-303.

    Banana plant has the characters of fruiting in high position and of hanging in non-fixed orientation, which is not conducive to the flower removal, bud removal breaking, pesticide spraying, bagging and harvesting of banana fruit in production, and make it vulnerable to wind damage, causing lodging and breaking. In order to reduce the height position of banana fruit, make it hang fruit directionally, facilitate management, realize mechanized harvest and improve field management efficiency, a guide outlet was excavated at the lower position on one side of banana pseudostem by physical method to guide banana to fruit at the lower position and predetermined direction, and the differences in fruit characters between physically induced fruit and naturally formed fruit were studied. The results showed that opening the outlet by physical method could guide the banana fruit grow in a low position and a predetermined direction. The average fruit yield per plant was 21.47 kg (with a variation range of 11.5 kg to 36.15 kg), the average number of fruit fingers per plant was 187(with a variation range of 137 to 237), the average weight of single fruit finger was 120 g (with a variation range of 60 g to 190 g), the average length of fruit axis was 41.82 cm (with a variation range of 27.5 cm to 54.5 cm), the average length of outer arc of fruit finger was 17.88 cm (with a variation range of 13.4 cm to 21.1 cm), the average perimeter of fruit finger was 11.44 cm (with a variation range of 9.6 cm to 12.9 cm). Correlation and regression analysis showed that the fruit weight per plant, fruit axis length and fruit finger length were significantly negatively correlated with the time interval from opening outlet day to heading fruit day, respectively. Compared with the natural heading fruit, there was no significant difference in average fruit weight per plant, average total number of fruit fingers per plant and average number of fruit fingers per comb, there was no significant difference in the thickness of the fruit fingers and the curvature of the fruit fingers; but there was significant difference in average weight of single fruit and of fruit axis respectively; The length of fruit axis and the length of fruit finger and the spacing between fruit combs was significantly shortened respectively, the differences are all very significant.

  • Qiufei WU, Cheng YANG, Shuyan ZHANG, Lu WEI, Meili FENG, Rui LI, Lixia ZHOU, Hongxing CAO
    Chinese Journal of Tropical Crops. 2024, 45(2): 234-246.

    Oil Palm (Elaeis guineensis Jacq.) is the most efficient oil-producing plant in the world. Fruit development is the basis of yield formation, but rancidity occurs after 24 h of harvesting, which seriously affecting the quality of palm oil. At present, the key regulatory genes and pathways for the differences in the synthesis of free fatty acid metabolism in pulp development and postharvest fruits have not been identified. In this study, oil palm fruits were collected from 95 days (MS1), 125 days (MS2), 185 days (MS3), 24 h (MS4) and 36 h (MS5) after pollination. The second generation high-throughput transcriptomics (RNA-Seq) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to analyze the transcriptomes and metabolomes of the fruits during the development and postharvest storage. The unsaturated fat of oil palm was significantly higher than that of fatty acid during the middle and late stages of fatty acid accumulation, LACS4, LACS4-X1, FATA, FATB, KASⅠ, KASII, SAD1 were highly expressed in pulp and were positively correlated with oleic acid, linoleic acid, palmitic acid, palmitoleic acid acid, stearic acid and linolenic acid, DGAT and PDAT were over-expressed in the pulp and negatively correlated with the content of the six fatty acids, indicating that the expression of the above-mentioned genes may promote and inhibit the synthesis and accumulation of the fatty acids in oil palm fruit, respectively, suggesting that LACS4, LACS4-A1, FATA, FATB, KASⅠ, KASII and SAD1 may be the key genes with high content of unsaturated fat during postharvest storage. GDSL2, GDSL7, SAD2, LACS9 genes and GDSL1, KAT were positively and negatively correlated with oleic acid, and negatively and positively correlated with palmitic acid, palmitoleic acid acid, stearic acid, linoleic acid and linolenic acid, respectively, suggesting that GDSL2, GDSL7, SAD2 and LACS9 might promote oleic acid production and inhibit palmitic acid, palmitoleic acid acid, stearic acid, linoleic acid and linolenic acid production during rancidity, while GDSL1 and KAT might inhibit linolenic acid production, suggesting that GDSL2, GDSL7, SAD2 and LACS9 are the key genes causing oil palm rancidity after harvest. The aim of this study is to provide candidate genes for improving unsaturated fat content and altering fatty acid composition by using molecular biotechnology, and to provide theoretical reference for screening unsaturated fat and storability varieties.

  • Houhua FU, Hongjin WEI, Xinyan CHEN, Liang MA, Shipin CHEN
    Chinese Journal of Tropical Crops. 2024, 45(2): 264-268.

    In recent field survey and specimen examination, eight species of pteridophytes belonging to seven genera in five families are reported as new records in Fujian province, Gymnocarpium oyamense (Baker) Ching, Pronephrium parishii (Beddome) Holttum, Athyrium drepanopterum (Kunze) A. Braun ex Milde, Diplazium okinawaensis Tagawa, D. hainanense Ching, Hymenasplenium excisum (C. Presl) S. Lindsay, Asplenium ensiforme Wallich ex Hooker & Greville and Microsorum membranaceum (D. Don) Ching. Among them, G. oyamense is a newly recorded genus in Fujian province, and P. parishii, A. drepanopterum, D. okinawaensis, D. hainanense and M. membranaceum are newly recorded species in East China.

  • Guangdong HAN, Fengpei SUN, Ziying REN, Jingwen CAO, Aiping GAO, Jianfeng HUANG, Zhizhong SONG
    Chinese Journal of Tropical Crops. 2024, 45(2): 225-233.

    Iron (Fe) is one of the essential trace mineral elements in plants to maintain normal growth and development that plays an important role in various life processes. Researches towards molecular mechanism of Fe uptake, transport and distribution are mainly focused on the annual model plants. Biological functions of genes towards Fe uptake and transport in fruit trees are still unknown. In this study, 11 ferric reduction oxidase encoding genes (FROs) were isolated and identified from diploid mango Guire 82, named by MiFRO1–MiFRO11. All mango FRO had ten typical motifs except for MiFRO1 lacking Motif2–Motif5. All mango FRO possessed similar tertiary structure, with the exception that MiFRO3 exhibited distinct tertiary structure. The amino acid sequences of FRO from 11 plants shared an overall identity of 42.07%, while mango FRO shared an overall identity of 62.43%. Phylogenetic tree analysis showed that mango FRO were prone to be closely clustered together lonely, which was far away from the homologs of the other ten plants in genetic distance. Quantitative real-time PCR (qRT-PCR) analysis showed that MiFRO3 was the most abundant expressed gene during different parts of Guire 82 mango on the whole. In particular, MiFRO4, MiFRO5, MiFRO8 and MiFRO11 were highly expressed in the leaves of both mature trees and grafted seedlings. MiFRO6 and MiFRO7 were highly expressed in phloem or stem, MiFRO1 and MiFRO10 were highly expressed in young fruits, MiFRO2 and Mi-FRO9 were highly expressed in seedling roots, while MiFRO3 was highly expressed in full bloom flowers. In addition, expression of FRO in mango roots were mainly induced under iron depletion and NaCl stress, respectively, while Mi-FRO3, MiFRO5 and MiFRO8 were significantly reduced under iron toxicity. Expression of MiFRO2, MiFRO5 and Mi-FRO7 were increased under ABA treatment, and MiFRO1 and MiFRO5 were enhanced under PEG treatment. Expression of MiFRO2, MiFRO6 and MiFRO7 were decreased under low temperature (4 ℃). However, FRO changed little under heat stress (45 ℃) in mango roots. This study would provide gene resources to elucidate the molecular mechanisms of Fe uptake and transport in mango, and lay a theoretical foundation to reveal Fe nutrition and high utilization in tropical fruit crops.

  • Yinglin HUANG, Xiaohui ZHANG, Miao ZHANG, Bin CHEN, Binghua CHEN
    Chinese Journal of Tropical Crops. 2024, 45(2): 259-263.

    In the current study, one newly recorded genera of wild orchids, Neuwiedia Blume, as well as five newly recorded species, including Goodyera brachystegia Hand. -Mazz, Neuwiedia zollingeri var. singapureana (Baker) E. F. de Vogel, Odontochilus drymoglossifolius (Hayata) T. Yukawa, O. saprophyticus (Aver.) Ormerod and O. yakushimensis (Yamam.) T. Yukawa in Fujian province were illustrated. The voucher specimens of the plants are preserved in the Herbarium of Fujian Normal University (FNU). The discovery of the newly recorded orchids has great significance for further studies on the diversity and conservation of Orchidaceae in Fujian, China.

  • Yiwei ZHOU, Feixiong LIAO, Yuanjun YE, Xiaofei LIU, Yechun XU, Jianjun TAN, Jinmei LIU
    Chinese Journal of Tropical Crops. 2024, 45(2): 269-277.

    Spathiphyllum Schott is a perennial herb of Araceae, which is an important foliage plant for ornamental. Phenotypic diversity of germplasm resources is the basis of ornamental plants breeding and application. In the current study, 27 important ornamental traits of 20 Spathiphyllum germplasm resources were observed and the phenotypic diversity was analyzed by multivariate statistical analysis methods including variance analysis, correlation analysis, hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results of variance analysis showed that the coefficients of variation of the 16 quantitative traits ranged from 27.2% to 69.9%. The plant height, number of shoots, number of leaves, blade width, petiole diameter, spadix length and number of flowers were highly variable, while the plant width and spadix diameter had small variation. Eleven descriptive traits could be divided into 2~4 grades according to the observed characteristics. And the Shannon-Wiener indices of 11 descriptive traits ranged from 0.20 to 1.01, among which the Shannon-Wiener indices of leaf shape were the highest, whereas that of perianth separation and perianth color were the lowest. The hierarchical cluster analysis tree of 27 traits supported that when the euclidean distance was 3, they could be divided into two groups: Group A and Group B. The result of Pearson correlation analysis revealed that the correlation coefficient between 27 traits ranged from -0.72 to 0.91. In Group A, most of the traits were significantly correlated with each other, and the correlation coefficients between bud length and bud width, bud length and inflorescence length were 0.91. In Group B, most of the traits pairs were not significantly correlated. Both hierarchical cluster analysis and principal component analysis supported that the 20 Spathiphyllum germplasm resources could be divided into 2 Groups (Group I and Group II) based on data of 27 traits. Group I contained 7 accessions including S. cannifolium, S. ortgiesii, S. Clevelandii, S. Bright, S. Princess, S. Middle Flower and S. Sensation, and they were taller and had larger leaves, larger spathes, and larger spadixes. Group II was consisted of S. floribundum, S. Coddy Color, S. Water Grass, S. Parrish, S. Mini, S. Vicki Lynn, S. Mojo, S. Tyler Green, S. Crisis, S. Sweet Chico, S. Sweet Claudio, S. Dark Green and S. Sunshine Dream. And the 13 accessions of Group II had more buds and leaves, and were smaller and more compact. The research results could provide a reference for evaluation and breeding of Spathiphyllum germplasm resources.

  • Fucheng LIU, Zhaojie LI, Wenwei CAI, Wei WU
    Chinese Journal of Tropical Crops. 2024, 45(2): 330-339.

    Reasonable planting density and depth are the common cultivation techniques to increase sugarcane yield per unit area. However, the effect on sugarcane lodging is often neglected when the yield is increased. Sugarcane variety Zhongtang 3 was used as the experimental material to determine the effect of different planting density and depth on the yield and lodging. Four planting density 3.0, 4.5, 6.0 and 7.5 buds/m2 and two planting depth of shallow planting (30 cm) and deep planting (40 cm) were designed in the experiment. The agronomic characters, lodging related index (root lodging and stalk lodging) and yield of sugarcane were measured. The results showed that as the growth period of sugarcane continued to advance, the safety factor of sugarcane root and stem gradually decreased, and the risk of root lodging and stem lodging of sugarcane was higher at 180 days after planting, which was in a sensitive period. When the planting density increased from 3 buds/m2 to 6 buds/m2, sugar yield (+32%) and yield (+36%) of sugarcane were significantly increased, and the stem lodging resistance of sugarcane was also increased. However, when the planting density was further increased to 7.5 buds/m2, the sugar yield and yield did not increase significantly, but the risk of root lodging was increased. Compared with planting depth of 30 cm, planting depth of 40 cm had a tendency to increase sugar yield (+2.8%) and yield (+4.8%), although there was no significant difference between them. Therefore, considering sugar yield, yield and lodging resistance of sugarcane, we believe that planting depth of 40 cm and planting density of 6 buds/m2 can improve lodging resistance of sugarcane while ensuring yield and sugar yield.

  • Shixing LUO, Yuming QIN, Guodi HUANG, Yujuan TANG, Yu ZHANG, Riwang LI
    Chinese Journal of Tropical Crops. 2024, 45(1): 41-48.

    There are about 69 species of Mangifera in the world, and 8 species are mainly distributed in China. The long history of mango cultivation in China has resulted in many natural hybrids with local characteristics. In the process of continuous coordinated development with the environment, the appearance of mango, such as branches, leaves and fruits, has changed to some extent, but its pollen has formed unique morphological characteristics while maintaining genetic conservatism and stability. In order to further study the taxonomic significance of the pollen morphology of mango plants and clarify the phylogenetic relationship between mango natural hybrids, this study carried out palynological research and genetic relationship analysis on mango germplasm based on the microscopic characteristics of pollen, and observed the pollen morphology and pollen exine ornamentation of 32 mango materials from two species of mango using scanning electron microscopy. On this basis, cluster analysis was carried out on six quantitative characters of pollen. The results showed that the pollen of 32 the mango germplasms belonged to N3P4C5 type. The polar view was 3-split triangle, and the red view was nearly elliptical. There were three germination grooves, which almost reached both ends; There were differences in the shape and size of pollen, the width of germination ridge, pollen ornamentation, the density and size of pollen outer wall mesh among the materials. Stripes or reticular ornamentation and pits were all over the surface of pollen grains. Most mango pollen belongs to reticular ornamentation. Mesh shapes were diverse, mainly circular and long, with rough ridges. Mesh distribution density varied among different materials. According to the cluster analysis of quantitative characters such as pollen grain size, pollen morphology, germination ridge width, mesh size and mesh density, the 32 mango germplasms could be divided into three groups when the similarity distance was 15. Mango resources from Southeast Asia, such as Machesu M. indica, Siam Mango M. indica, Ren He Carabao M. indica, were clustered into one group in the pedigree map, showing certain regional characteristics; Yun Nan Tu Mango M. indica, Bruce Mango M. indica and Amemwins No.26 M. indica with narrow germination ridge were divided into one type; M. persiciformis, collected M. persiciformis and common domestic M. indica. cultivation species were grouped into one group. The original wild species, Bai Hua M. indica, was grouped with No.1 M. persiciformis, No.2 M. persiciformis, No.3 M. persiciformis, and No.4 M. persiciformis. The resource had the characteristics of primitive and wild types. This study would provide palynological basis for the classification, genetic relationship and evolution of mango pollen morphology.

  • Jinying WANG, Huasheng LI, Jinying LU, Changfu CAI, Bangping CAI
    Chinese Journal of Tropical Crops. 2024, 45(1): 60-67.

    With the development of the aerospace industry, the method of combining traditional breeding technology with aerospace mutagenesis technology to achieve breeding goals has been widely recognized by breeding experts. The problems faced by the scale of the banana industry in Fujian make the breeding of new banana varieties an important issue. In the early stage of this study, Brazil banana was used as the female parent. On the basis of space mutation, through continuous cultivation, screening and observation, two materials with obvious differences in biological and morphological characteristics were selected. In order to identify the genetic specificity of the two independently bred aerospace banana materials, the ISSR molecular marker technology was used in this study to screen out two primers with good polymorphism from 30 primers to analyze the two aerospace banana materials and 18 existing banana varieties. A total of 17 clear DNA bands were amplified by the two primers screened, of which 13 were polymorphic bands, accounting for 76.47% of the total bands, showing a high polymorphism at the DNA molecular level of banana materials. Electrophoresis showed that, combined with ISSR primers UBC881 and UBC847, the two aerospace banana materials had specific amplification bands, which could be distinguished from the other 18 banana varieties. Cluster analysis results showed that the genetic similarity coefficients between the 20 banana germplasm materials ranged from 0.545 to 1.000, with an average of 0.905; when the genetic similarity coefficient was 0.960, there were obvious genetic differences between the two bred aerospace banana materials, and the two bred aerospace banana materials with the female parent, and with other 17 banana germplasms. The results of this study would provide a strong basis for the breeding and identification of new varieties of aerospace bananas.