‘Huangjinmi’，a new early-ripening table grape cultivar with muscat flavor，is derived from the cross of‘Red Globe’and‘Xiangfei’. The average cluster weight is 703.5 g，and the average single berry weight is 9.5 g. The berry is round，yellow-green or golden yellow，crisp and hard. The soluble solids content is 19.0%，and the titratable acid content is 0.58%. It had a high yield（26 300 kg · hm^-2），early bearing，and long shelf life. It is suitable for open field and protected cultivation in the Beijing，Tianjin，Hebei and other areas with similar ecological conditions，and for rain shelter cultivation in the rainy regions of the South.

Flavonoids are a class of secondary metabolites with ‘flavan’ skeleton and thousands of derivatives. The biosynthetic pathways of flavonoids are complicated，and some of them and related enzymes have been analyzed. Flavonoids play important roles in the growth and development of plants and the formation of flowers and fruits. Studies revealed that flavonoids can response to stresses and improve the tolerance and resistance of plants. This article reviews the biosynthetic pathways and molecular regulation mechanism of flavonoids in plants，the response of flavonoid pathways to different stresses，the main roles and mechanisms of flavonoids，and the future research directions. Thus，this article is expected to providing theoretical support for the targeted cultivation of horticultural crop varieties with highly resistant，deep processing，and product development.

Citrus genetic improvement has achieved a great progress during the last six decades in China. A repository harboring more than 1 700 accessions of Rutaceae in Chongqing and an embryogenic callus collection including more than 100 varieties in Wuhan have been established,respectively. Continuing exploration of citrus germplasm resulted in the identification of wild Daoxian tangerine,Honghe papeda and the mini-citrus,a mono-embryonic Hongkong kumquat for functional genmics research. A new type of rootstock,Ziyang Xiangcheng（Citrus junos）has been utilized in Chinese citrus industry. A total of 122 citrus varieties including 121 for scion and one for rootstock have been registered or protected by PVP. Out of the scion varieties,88.5% is from the natural mutation including the bud-sport and chance seedling variation,and the rest from artifically created mutants,such as the irradiation,hybridization and protoplast fusion etc. These varieties covered nearly all types of citrus,including loose-skin mandarin,sweet orange and pummelo etc,with improved seedlessness,mature season and fruit color etc. The omics technologies have been widely used in citrus genetic improvement in China. Genomes including sweet orange and other main citrus species have been sequenced and assembled during the recent decade,as has accelerated cloning of the key genes controlling import agronomic traits,such as the polyembryonic related gene CitRWP etc. Genetic transformation and gene editing are also setup in Citrus. These achievments have laid a solid base for citrus genome-design breeding for the future.

‘Danxiahong’is a new red skin pear cultivar selected from the cross‘Zhongli 1’בHongxiangsu’. The shape of fruit is nearly round. The fruit size is big，and the average fruit weight is 260 g. The fruit skin is green covered with red on the side exposed to the sun. The flesh is white，crisp，rich juice，sweet，with litter fragrant. The soluble solids content is 13.5%. It matures in mid and late August in Zhengzhou City，Henan Province. The fruit have long storage life but not resistant to bumping. The yield is about 45 000 kg • hm-2 at full fruit stage.

The gene structure analysis,protein conserved motif identification,subcellular localization prediction,synteny analysis,phylogenetic analysis,and cis-acting elements analysis of Growth-regulating factor（GRF）family members were performed. Expression patterns of grape GRF genes in different plant parts and against different hormone applications were analyzed. Further expression patterns were compared during different stages of seed development in seeded and seedless cultivars. Eight grape GRF genes were identified and divided into four groups（A-D）. Seven of the genes were unevenly distributed on six chromosomes having and the number of amino acids was 213-604. All grape GRF proteins were predicted in the nucleus. Moreover,VvGRFs in the same clade showed conserved exon-intron structure and motif distribution patterns. All GRF proteins contained QLQ and WRC domains in the N-terminal region and at least one TQL or FFD domain in the C-terminal region. Synteny analysis showed that VvGRF3 and VvGRF4 were segmentally duplicated. Various cis-acting elements related to growth and development,hormones response,and stresses were found in the promoter region of VvGRF genes. Expression analysis illustrated that most of the VvGRFs were highly expressed in vegetative organs i.e. leaves. However,VvGRF2 was highly expressed in reproductive organs like flowers and fruits. The expression of VvGRF3 and VvGRF6 was significantly higher during seed development in seedless grapes as compared to seeded grapes,while VvGRF8 showed high expression in seeded grapes. The expression of VvGRF genes was induced against GA₃ and IAA treatments,and most of the VvGRFs were down-regulated at 0.5 or 1 h.

In this study，ninety apple cultivars were used as experimental materials to evaluate cold tolerance by a relative electrical conductivity test. Genome-wide association analysis was conducted on 1 247 162 SNPs detected in apple accessions by genome resequencing technology，and candidate genes significantly associated with cold tolerance were selected. Three cultivars with the strongest cold tolerance were identified，and their relative electrical conductivity was all less than 40%，which were‘Jinhong’，‘Ederbostdorf’and‘Haralson’. Based on the association analysis using 1 247 162 high-quality SNPs and index of relative electrical conductivity characterizing cold tolerance，five significant correlated loci related to cold tolerance were identified，which were distributed on chromosome 4，15，and 16，respectively. Three candidate genes TIF3B1（MD04G1241100），COR47（MD15G1003900），and MD16G1069900 closely related to cold stress tolerance were identified.

To evaluate the effect of apple dwarfing rootstocks on the scion growth and drought resistance,we used four-year-old apple trees with different scion-rootstock combinations（‘Fuji’/G935,‘Fuji’/M9-T337 and‘Fuji’/SH6）. Morphology analysis of these three apple trees showed that‘Fuji’scion grown on SH6 exhibited significantly reduced leaf thickness,palisade tissue thickness and stomatal density compared with the‘Fuji’grafted on G935 and M9-T337. Furthermore,three kinds of apple trees were exposed to drought stress treatment for determining their drought tolerance and recovery feature after re-watering. The analysis of drought-related physiology parameters indicated that compared with the other two grafted combinations,the‘Fuji’/SH6 combination displayed enhanced water use efficiency（WUE）,osmoregulation substance content,superoxide dismutase（SOD）activity and ABA content,and the reduced malondialdehyde（MDA）content,net photosynthetic rate（P_n）,transpiration rate（T_r）and stomatal conductance（G_s）under drought stress. The results of membership function analysis showed that‘Fuji’/SH6 had the optimal drought resistance,followed by‘Fuji’/G935,and‘Fuji’/M9-T337 had the worst drought resistance. Overall,‘Fuji’/SH6 grafted combination showed excellent drought resistance.

‘Hongcuinuo’is a new high-quality and late-maturing litchi cultivar selected from open-pollinated seedlings of litchi in Guangdong. The average fruit weight is 23.6–28.6 g. The fruit is mostly long heart-shaped with scarlet skin，and the flesh tastes crisp and sweet（17.7%–19.1% TSS）. The seeds are generally aborted with an abortion ratio 90% and flesh recovery of 74.7%–81.1%. The contents of titratable acid，juice vitamin C and total sugar in the pulp were 0.15%–0.25%，0.77 mg • mL-1 and 160.5 g • L-1. The average yield of top grafting was 12 000 kg • hm-2 in the 5th year. The maturity period is early to mid July in Huilai County Guangdong Province.‘Hongcuinuo’is a promising cultivar for its high quality，late-maturity，good graft compatibility，easy to flower and fructify as well as high and stable yield.

‘Liyuan Zhenzhu 4’，a new sour jujube（Ziziphus spinosa Hu.）cultivar，was selected from seedlings resources. The fruit is round. The average fruit weight is 1.67 g，the soluble solids content is 18.6%，and the vitamin C content is 9.38 mg • g-1. The seed kernel rate is 32.8%. The fruit ripens in early September with developing period of 90 days. It is highly resistant to fruit cracking，and also it has high and stable yield. The average output is 22 100 kg • hm-2.

‘Zhejiao 10’，a new late maturing double-harvest water bamboo cultivar developed by systematic selection from‘Suozijiao’mutants after 10 years，has a luxuriant growth. The harvest period of ‘Zhejiao 10’is about 13 days later than that of‘Suozijiao’in fall. Gross harvested weight of‘Zhejiao 10’in fall is 136.8 g per each，net weight is 90.6 g per each，and the average yield is 23 460 kg · hm^-2. The harvest period of‘Zhejiao 10’is about 6 days later than that of ‘Suozijiao’in summer. Gross harvested weight of‘Zhejiao 10’in summer is 151.8 g per each，net weight is 103.3 g per each，and the average yield is 40 020 kg · hm^-2. The succulent stem has 3-5 joints，and the bud is white. It has glossy surface，fine and tender quality. The cultivar was suitable for planted in Zhejiang Province.

In this article,the development history of protected horticulture in China during the last 60 years has been reviewed briefly including,the accomplishments of protected horticulture in China in industrial growth,scientific and technical innovation,talents training,and team platform construction. Moreover,the potential for future development and the main tasks of protected horticulture in China are prospected.

‘Jiayou 1’，a new jujube cultivar for dehydration usage，selected from the excellent single plant of Youzao in Jiaxian County，Yulin City，Shaanxi Province. The fruit is long and oval，with a longitudinal diameter of 4.84 cm and a transverse diameter of 2.92 cm. The average single fruit weight is 16.74 g，and the maximum is 26.8 g. The fruit ripens15 days later than that of local jujube in Jiaxian County，so it effectively avoids the disaster of fruit cracking in rainy days. The cultivar has high yield，and 2-year-old fresh fruit yield per plant is 4.93 kg which is 15.8% higher than the local jujube Jiaxian County. It is suitable to be popularized and applied in jujube area and similar ecological areas in Northern Shaanxi.

‘Liyuan Zhenzhu 8’，a new sour jujube（Ziziphus spinosa Hu.）cultivar，was selected from seedlings resources. The fruit is obovate. The average fruit weight is 1.4 g，the soluble solids content is 29.3%，and the titratable acid content is 6.0%. The seed kernel rate is 27.3%. The fruit ripen in mid-late September with developing period of 105 days. It has high and stable yield. The average output is 21 700 kg • hm-2.

Browning of pear flesh is an important problem affecting its quality. In this experiment，Browning varieties‘Baozhu’，‘Pingguoli’and non-browning varieties‘Fengshui’，‘Honghuada’were used to study the physiological mechanism of pear flesh browning，by measuring the changes of browning degree，phenolics and related enzyme activities during fruit development. The results showed that the browning degree，phenolic content and some enzyme activities of pear flesh decreased gradually with The growth and development of the fruit. Arbutin，chlorogenic acid and epicatechin were the main phenolic compounds in pear fruit from young fruit stage to mature fruit stage，accounting for more than 90% of the total phenolic content. The contents of arbutin and chlorogenic acid in the fruits of the two browning varieties were higher than those of the two non-browning varieties. According to the correlation analysis between fruit browning degree and phenolic substance content，single phenolic substance had little effect on fruit browning in young fruit stage，and phenolic substance strongly correlated with fruit browning in late fruit growth were arbutin，catechin，chlorogenic acid and caffeic acid. In the process of fruit growth and development，the PPO，PAL activities and total phenol content of browning varieties were higher than those of non-browning varieties. The PPO activity of the browning varieties was significantly different from that of the non-browning varieties at young fruit stage（P < 0.05），and it was not significantly different at mature fruit stage. The activities of PPO and PAL were significantly correlated with the contents of most phenolic substances in the fruits of the four varieties. The study on fruit browning at different development stages should take PPO activity and total phenolic content into consideration.

To explore the role of peroxidase（POD）gene family members under stress conditions in apples,51 apple POD（MdPOD）family members were identified through multiple sequence alignments in which the reported Arabidopsis thalianaPOD genes were adopted,and their expression under stresses are analyzed. The results show that the 51 family members scatter in 13 chromosomes,encoding 95 to 1 433 amino acids,protein molecular weight ranges 10.18 to 161.02 kD,and isoelectric point（pI）ranges from 4.36 to 9.90. Further analysis indicates that the gene family is divided into six subfamilies,and the number of exon is 1 to 40. Selective pressure analysis shows that 20 gene pairs are subjected to purification selection in the evolutionary process. Subcellular localization shows that MDPOD15 is mainly presented in the cell membrane,cytoplasm,nucleus and chloroplast. The expression profile of gene chips displays that MdPOD are highly expressed in apple’s flowers,leaves and fruits. Real-time quantitative PCR （qRT-PCR）indicates that the expressions of most genes increased after ABA treatment for 2 h,and then decreases. Under PEG treatment,the expressions of 51 MdPODgenes firstly increase and reach the peak value at 12 h,while under the NaCl treatment,the expressions of MdPOD genes increase with the prolongation of time and reach the peak value at 24 h. The transient expression of MdPOD15 in tobacco leaves shows that MdPOD15 is expressed in the cell wall,cytoplasm and nucleus,and the overexpression of MdPOD15 in apple callus can mitigate the degree of cell damage caused by abiotic stress. Therefore,MdPOD genes may play different roles in different periods of time under different abiotic stresses.

In order to study the role of apple ELO gene family in wax synthesis and cold resistance,bioinformatics methods were used to identify and analyze the ELO family members in the whole apple genome. The results showed that the MdELO gene family consisted of seven members,which were unevenly distributed on three apple chromosomes（Chr2,Chr8 and Chr15）. The MdELO protein contains 211-305 amino acid residues with isoelectric points ranging from 9.43 to 11.62. The results of subcellular localization showed that MdELO protein was distributed in the nucleus,cell membrane and chloroplast. The analysis of cis-acting elements showed that the 2 000 bp sequences upstream of the seven MdELO promoters were distributed with response elements such as hormones,environmental adaptability and stress induction. The wax content in different apple cultivars was further determined,and the results showed that the wax content of‘Oregon Spur Delicious’was significantly higher than that of‘Miyazaki’;On the other hand,from the it perspective of wax morphology and cuticle morphology,the wax of‘Oregon Spur Delicious’was needle-like and closely distributed,and the cuticle structure of its branches was close and smooth,while the wax of‘Miyazaki’was loose and lumpy,and the cuticle structure of its branches was loose and the surface was rough. Additionally,the proline,relative electrical conductivity and starch phosphorylase of the two apple branches increased firstly and then decreased with the extension of the overwintering period,and the amylase increased gradually,among which the content and activity of all indexes of‘Oregon Spur Delicious’were higher than that of‘Miyazaki’. The changes of the above indexes showed that the cold resistance of‘Oregon Spur Delicious’was significantly higher than that of‘Miyazaki’. It was found that the expression of ELO family members can be detected in the roots and leaves through qRT-PCR analysis,and the expression level displayeded certain differences. Most of them showed a trend of rising first and then falling,and the expression level is the highest at 12 h or 24 h,indicating that this family members may play an important role in low temperature stress.

The Pepper originated in the semi-arid area in central and southern Bolivia where the annual rainfall is less than 500 mm. This is a subtropical frost-free area. The original wild species are perennial herbs. According to the analysis and study of the starch granules,the Capsicum starch microfossils have been found dating from 8 000-7 500 years ago. Over thousands of years,Capsicum seeds spread out from Bolivia with the help of birds and indigenous peoples,thus spreading throughout South and Central America,then to the southwest of North America. In different ecological regions,more than 10 wild relatives and about 20 wild non-relatives of cultivated species have evolved. Capsicum cultivars evolved from the common ancestor Capsicum chacoense. The purple flower ancestors migrated to the Andes highlands and evolved to Capsicum pubescens. And the white flower ancestors migrated to the relatively dry area of southern Bolivia to evolve to Capsicum baccatum,continuing to migrate to the humid Amazon basin and evolve to the common ancestors of Capsicum annuum,Capsicum frutescens L. and Capsicum chinense Jacquin. They continued to migrate outward,evolving Capsicum annuum in Mexico and northern Central America,Capsicum frutescens L. in the Caribbean,and Capsicum chinense Jacquin in the northern valleys of the Amazon Basin. The pepper domestication started by removing the wild species from the original area for artificial cultivation. The wild species with the fruit small,single-color,upward-facing and easily falling off were domesticated into cultivated species with the fruit succulent,various-shaped,colorful,downward-facing,and not easy falling off,i.e. good economic benefits. Capsicum annuum was the first cultivated species domesticated in Mexico and Central America more than 6 000 years ago,and the other four cultivated species had been cultivated for at least 4 000 years,which are the oldest cultivated plants in America.

A total of 176 Passiflora edulis leaf samples showing mosaic,crinkle and deformation were collected from Sanya and Wuzhishan of Hainan Province from May to July 2020. Seven viruses were detected by PCR and RT-PCR including cucumber mosaic virus （ CMV ）,cucurbit aphid-borne yellows virus （ CABYV ）,East Asian Passiflora virus （ EAPV ）,Telosma mosaic virus （ TeMV ）,passion fruit woodiness virus （ PWV ）,Passiflora mottle virus （ PaMV ） and tomato yellow leaf curl virus （ TYLCV ）. The result showed that TeMV was the most prevalent virus with infection rate of 52.27%,followed by PaMV（43.75%）,CMV and EAPV （ 28.98% ）,PWV （ 22.73% ）,TYLCV （ 9.09% ） and CABYV （ 4.55% ）. TeMV,PaMV,CMV,EAPV and PWV may be the main viruses infecting P. edulis in Sanya and Wuzhishan. 78.91% of samples were detected co-infection with a total of 32 kinds of co-infection types,in which co-infection of two to four viruses commonly occurs. Three complete genome sequences of TYLCV from P. edulis were determined to be 2 781 bp and encoded six open reading frames （ ORFs ）. Both the identity and phylogenetic analysis based on the complete genome showed that all the three TYLCV isolates belonged to TYLCV Israel strain with nt identity ranging from 98.85% to 99.14%,and clustered in the same branch with the four TYLCV isolates from other crops in Hainan. To our knowledge,this is the first report of TYLCV in P. edulis.

‘Liyuan Zhenzhu 14’，a new sour jujube（Ziziphus spinosa Hu.）cultivar，was selected from sour jujube seedlings resources. The fruit is oval. The average fruit weight is 1.51 g，the soluble solids content is 14.2%，and the vitamin C content is 8.48 mg • g-1. The flesh has sour flavor. The seed is full and the seed kernel rate is 26.22%. The fruits ripen in late August. It has high and stable yield，and the average output is 22 600 kg • hm-2.

This review briefly describes the carotenoid metabolic pathway and main flux-controlling steps for carotenoid accumulation in plants. It highlights our recent understanding of the regulatory mechanisms underlying carotenoid accumulation at transcriptional，post-transcriptional，post-translational and epigenetic levels.