Background

Appropriate flowering time is very important to the success of modern agriculture. Maize (Zea mays L.) is a major cereal crop, originated in tropical areas, with photoperiod sensitivity. Which is an important obstacle to the utilization of tropical/subtropical germplasm resources in temperate regions. However, the study on the regulation mechanism of photoperiod sensitivity of maize is still in the early stage. Although it has been previously reported that ZmCCT is involved in the photoperiod response and delays maize flowering time under long-day conditions, the underlying mechanism remains unclear.

Results

Here, we showed that ZmCCT overexpression delays flowering time and confers maize drought tolerance under LD conditions. Implementing the Gal4-LexA/UAS system identified that ZmCCT has a transcriptional inhibitory activity, while the yeast system showed that ZmCCT has a transcriptional activation activity. DAP-Seq analysis and EMSA indicated that ZmCCT mainly binds to promoters containing the novel motifs CAAAAATC and AAATGGTC. DAP-Seq and RNA-Seq analysis showed that ZmCCT could directly repress the expression of ZmPRR5 and ZmCOL9, and promote the expression of ZmRVE6 to delay flowering under long-day conditions. Moreover, we also demonstrated that ZmCCT directly binds to the promoters of ZmHY5, ZmMPK3, ZmVOZ1 and ZmARR16 and promotes the expression of ZmHY5 and ZmMPK3, but represses ZmVOZ1 and ZmARR16 to enhance stress resistance. Additionally, ZmCCT regulates a set of genes associated with plant development.

Conclusions

ZmCCT has dual functions in regulating maize flowering time and stress response under LD conditions. ZmCCT negatively regulates flowering time and enhances maize drought tolerance under LD conditions. ZmCCT represses most flowering time genes to delay flowering while promotes most stress response genes to enhance stress tolerance. Our data contribute to a comprehensive understanding of the regulatory mechanism of ZmCCT in controlling maize flowering time and stress response.

This study was carried out during 2011 and 2012 seasons on "Manfalouty" pomegranate cv. grown at the experimental orchard of Pomology Department, Faculty of Agriculture, Assiut University. The objectives of this study were examining the effects of pre-harvest spray with CaCl2 (4%) and GA3 (100 ppm) as well as post-harvest treatments with jasmine oil (2.5 cm3 /L), olive oil (2.5 cm3 /L), fiber gard (20 cm3 /L) and wrapping individually fruit with food polyolefin stretch as an improving effect in physicochemical characteristics of "Manfalouty" pomegranate cv. during storage under room temperature (22+5°C). The experiments were set up on split-plot arrangements in complete randomized block design (CRBD), with three replicates, 20 fruits each. According to the obtained results of this study, it could be deduced that pre-harvest spray with GA3 (100 ppm) gave in general, the best results on improving physical and chemical characteristics, followed by CaCl2 (4%) during the two growth seasons, as well as wrapping individually fruits with food polyolefin stretch gave the best quality during shelf-life period, followed by dipping fruits in both jasmine oil or olive oil and fiber gard during fruit storage under room temperature. Therefore, the authors recommended with wrapping individually fruits to keep fruits with good quality during fruit storage under room temperature.

This experiment was carried out during two successive seasons 2015 and 2016 on the orchard of Faculty of Agriculture, Assiut University. This study aimed to investigate the effect of potassium sulfate (K) fertilizer at different rates, application times and method of application on yield parameters and fruit properties of old trees of Balady orange cv. The obtained results showed that all K treatments significantly increased the fruit set (%), number of fruits/tree, total yield/tree (kg), fruit weight (g), fruit height and diameter (cm) as compared with control (untreated trees) during both experimental seasons. Moreover, the three times applications and foliar sprays were more effective than twice applications and ground adding of potassium sulfate (K), respectively. The lowest values of these parameters, were recorded in control (untreated trees), while the foliar application of 666 g + 90 mlsprays /tree of potassium sulfate (K) three times gave the highest values during both tested seasons.

Investigation was carried out during two consecutive seasons of 2017 and 2018 on ten grape cultivars namely Thomson Seedless ,Ruby Seedless (KingRuby), Red Roomy, Provano ,Black Moskate , Polomino , Rich Baba,Beauty Seedless, Bez El Naka and Bez El Anza grown in the orchard of Pomology Department at the Faculty of Agriculture, Assiut University .This study aimed to evaluate this cultivars regarding vegetative growth .The illustrated data revealed that, the average shoot length progressively increased with increasing the period of time. The last dates of estimation showed a slower increase of shoot length comparing with the earlier dates. Rich Baba and Ruby Seedless represented also higher values (80.41 and 80.1 cm2 , respectively) with no significant differences between them, however Bez-El-Anza exhibited the lowest value (49.54 cm2 ).Provano grape cultivar gave the highest pruning weight followed by Red Roomy and then Bez-El-Naka. The present study revealed that there were great differences between the studied grape cultivars

This study was conducted during two successive seasons 2017 and 2018 to study the effect of some oils immersing on the storability and quality of Balady mandarin (Citrus reticulate L.) fruits during the storage period. The post-harvest treatments were immersed with camphor oil, linen oil and imazalil either singly or in combination. The fruits were stored at cold condition 8±1°C with 85-90% RH. Samples of each treatment were randomly withdrawn monthly for 4 months. The results showed that fruit weight loss %, fruit decay %, total soluble solids %, sugar contents and TSS/acid ratio were significantly increased with prolonging the storage period. On other hand, the advanced storage period induced a gradual decrease of fruit juice percentage, fruits firmness, acidity % and vitamin C. All treatments caused a decrease in fruit weight and fruit decay percentage, fruits firmness, acidity % and vitamin C. Using oils resulted in the least fruit weight loss, whereas, imazalil treatment had the least fruit decay percentage. Also, all treatments improved the fruit quality during the storage period compared control. It could be concluded that oils plus imazalil coating maintained fruit freshness without negative effects of fruit quality parameters and seems to be the proper and ideal treatment to prolong cold storage of Balady mandarin fruits without great reduction in fruit quality.

This study was carried out during two consecutive seasons of 2013/2014 and 2014/2015 on the third and fourth ration of Williams banana plants. The plants are grown in a private Orchard located at Kom Ombo city, Aswan Governorate, Egypt. The compost as an organic fertilizer, enriched with EM or bio-mex was used as a partial replacement for the mineral-N fertilizer. The experiment was set up as a complete randomized block design. The results revealed that using the recommended dose of nitrogen (RDN) via 25% as a mineral source and 25 to 50% as an organic one enriched with 50 or 25% of EM or bio-mex significantly enhanced the length and circumference of pseudostem, leaf area and total leaf area/plant as well as percentage of N, P and K of leaves compared to use the RDN only as a mineral N fertilizer. Also, the N fertilization with a combination of mineral and organic N sources with a bio-fertilizer significantly increased the bunch weight and hand weight consequently increased the yield/plant, as well as improved the fruit quality compared to use the RDN only as a mineral source. The promotion on such growth and fruiting traits was associated with increasing percentage of bio-form from 25 to 50%. The organic fertilizer enriched with bio-mex significantly stimulated these traits more than its use with EM. It is evident that such N fertilization program is very important for the banana fruit production. It improve the nutrient status, yield and fruit quality of banana plants. In addition, it minimizes the production costs and environmental pollution which could be occurred with using chemical fertilizers

This study was carried out through 2014 and 2015 seasons to evaluate some seeded dry date palm grown in Aswan governorate, Egypt. Their local name, Abd elnaby 1, 2, 3, El-masry 1, 2, Khaled ebn elwalid, Abas gaffer, Radwan and Ali Aamer date palm compared to Sakkoty cv. which is one of the commercial dry cultivar vegetative traits. Yield components and fruit quality as well as numerical evaluation and molecular genetics were investigated. The obtained results indicated that Ali Aamer date palm type had the highest values of most studied vegetative traits compared to the other studied types. On the other hand, the least values of such traits were recorded of Sakkoty cultivar. El-masry 2 type gave the highest yield components followed by Khaled ebn elwalid and Radwan types, whereas, Abd elnaby 1 gave the least one compared to other studied types. No significant difference was found among Abd elnaby 2, Ali Aamer and Sakkoty cultivar. Khaled ebn elwalid type had the highest values of fruit quality followed by El-masry and Abas gaffer types, whereas, Sakkoty cultivar gave the lowest one compared to the other studied types. As the numerical evaluation of date palm types, it could be arranged in a descendingly order as follows: Khaled ebn elwalid (86.2), El-masry 2 (84.4), Ali Aamer (81.5), Abas gaffer (80.9), Radwan (77.9), El-masry 1 (77.3), Abd elnaby 3 (76.8), Abd elnaby 2 (72.7), Sakkoty (68.2) and Abd elnaby 1 (67.7 units). The ISSR data were used to estimate the genetic similarity among the nine date palm strains by using UPGMA computer analysis. The highest similarity index (1.0) was recorded between Abd elnaby 1 and Abas gaffer, while the lowest similarity index was detected (0.0) between El-masry 2 and Ali Aamer. A dendrogram for the genetic relationship among the nine date palm strains was found. These results revealed that seeded date palm named El-masry 2, Abas gaffer, Khaled ebn elwalid, Ali Amer and Radwan are considered promising to be new strains to obtain a high yield with good fruit quality compared to Sakkoty date palm cultivar