Inhibition of lateral shoot formation by RNA interference and chemically induced mutations to genes expressed in the axillary meristem of Nicotiana tabacum L.

Background Lateral branches vigorously proliferate in tobacco after the topping of the inflorescence portions of stems for the maturation of the leaves to be harvested. Therefore, tobacco varieties with inhibited lateral shoot formation are highly desired by tobacco farmers. Results Genetic inhibition of lateral shoot formation was attempted in tobacco. Two groups of genes were examined by RNA interference. The first group comprised homologs of the genes mediating lateral shoot formation in other plants, whereas the second group included genes highly expressed in axillary bud primordial stages. Although “primary” lateral shoots that grew after the plants were topped off when flower buds emerged were unaffected, the growth of “secondary” lateral shoots, which were detected on the abaxial side of the primary lateral shoot base, was significantly suppressed in the knock-down lines of NtLs, NtBl1, NtREV, VE7, and VE12. Chemically induced mutations to NtLs, NtBl1, and NtREV similarly inhibited the development of secondary and “tertiary” lateral shoots, but not primary lateral shoots. The mutations to NtLs and NtBl1 were incorporated into an elite variety by backcrossing. The agronomic characteristics of the backcross lines were examined in field trials conducted in commercial tobacco production regions. The lines were generally suitable for tobacco leaf production and may be useful as new tobacco varieties. Conclusion The suppressed expression of NtLs, NtBl1, NtREV, VE7, or VE12 inhibited the development of only the secondary and tertiary lateral shoots in tobacco. The mutant lines may benefit tobacco farmers by minimizing the work required to remove secondary and tertiary lateral shoots that emerge when farmers are harvesting leaves, which is a labor-intensive process.

Hop (Humulus lupulus L.) phenology, growth, and yield under subtropical climatic conditions: Effects of cultivars and crop management

Commercial hop (Humulus lupulus L.) production occurs predominantly in temperate climates. The objectives of this study were to characterize the phenology of hops under subtropical climatic conditions and to determine the growth and yield potential. Two field experiments were conducted in Florida, southeastern United States. Rhizomes were planted in April. Data were collected during the establishment year. In the first experiment, we evaluated 7 American, 5 European, and 1 Japanese cultivars in a randomized complete block design. Bine height, main bine number, lateral shoot number, and dry cone yield (10% moisture) were recorded. Yield varied considerably, ranging from 0 to 197 kg ha–1. The top three yielding cultivars were ‘Cascade’, ‘CTZ’, and ‘Nugget’, all of which were American cultivars. Yield had positive correlations with main bine number and lateral shoot number, but it had no significant correlation with bine height. In the second experiment, we determined the duration of each phenological stage in ‘Cascade’. Reproductive phenology was characterized by premature and nonsynchronous flowering. Prolonged flowering resulted in multiple harvests over 61 days, starting in mid-June. We also evaluated crop management treatments, which consisted of three levels of hill spacing (76, 91, and 107 cm) and two nitrogen (N) rates (109 and 130 kg ha–1) in a factorial combination. Treatments were arranged in a split-plot design with hill spacing as the main-plot factor. Yield on a per-area basis increased with reducing hill spacing and increasing N rate by 41% and 38%, respectively. Our results demonstrate unique reproductive phenology of hops under subtropical climatic conditions, which prevents once-overharvest but enables the off-season supply of fresh hops over an extended period. This study provides a benchmark to develop production strategies for hops suitable to subtropical climates.

Spatial metabolomics using imaging mass spectrometry to identify the localization of asparaptine in Asparagus officinalis

Spatial metabolomics uses imaging mass spectrometry (IMS) to localize metabolites within tissue section. Here, we performed matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance-IMS (MALDI-FTICR-IMS) to identify the localization of asparaptine, a naturally occurring inhibitor of angiotensin-converting enzyme, in green spears of asparagus (Asparagus officinalis). Spatial metabolome data were acquired with an untargeted manner. Segmentation analysis using the data characterized tissue-type-dependent and - independent distribution patterns in cross-sections of asparagus spears. Moreover, asparaptine accumulated at high levels in developing lateral shoot tissues. Quantification of asparaptine in lateral shoots using liquid chromatography-tandem mass spectrometry (LC-MS/MS) validated the IMS analysis. These results provide valuable information for understanding the function of asparaptine in asparagus, and identify the lateral shoot as a potential region of interest for multiomic studies to examine gene-to-metabolite associations in asparaptine biosynthesis.

Study The Influence of Lateral Shoot Removal And Foliar Application of Algamix on Vegetative Growth And Yield of Grapevine (vitis Vinifera L.) Cv. Zark

A field experiment was carried out in a private orchard located at Dargalle village, Duhok governorate, Kurdistan region, Iraq, during growing season of 2019 to investigate the effect of lateral shoots removal, spraying of three concentrations (0, 4 and 8 ml. L-1 ) of Algamix and their interaction on growth, yield and quality of ' Zark’ grapes. The results indicated that lateral shoot removal and both concentration of Algamix significantly increased leaf area and shoot length, as soon as TSS and total yield per vine. The interaction between the studies factors varied in their effect on the traits, the most important interaction was the interaction of lateral shoot removal + spraying of high concentration of Algamix (8 ml. L-1

Interspecific grafting between Gossypium hirsutum, G. barbadense and G. herbaceum lines

Seedling grafting could provide additional crop improvement strategies for cotton. However, there existed limited studies on interspecific grafting and approaches. Four different grafting approaches were developed and compared between lines representing three of the four cultivated cotton species G. hirsutum, G. barbadense and G. herbaceum. Grafting approaches of this study focused on the cotyledon node and cotyledon leaves retained on scions, rootstocks, without cotyledon node and cotyledon leaves on scions and rootstocks or halved cotyledon node and single cotyledon leaf on scions and rootstocks. Evaluations of the grafting approaches were made by comparing survival and growth rate during the second and fifth weeks after transplantation, respectively. The formation of any lateral shoots at the grafted sites were studied in two of four grafting approaches in the first and the second year during flowering stage. DNA alterations due to grafting were investigated using microsatellite markers. There were no statistically significant differences between grafts and their control in survival rate and locus specific DNA alteration. Growth rate and lateral shoot formation, on the other hand, were different among grafting types and grafts. We concluded that grafting without cotyledon node and cotyledon leaves on rootstocks, and with cotyledon node but without cotyledon leaves on scions were easy to perform and suitable for interspecific cotton grafting. Results suggested that grafting seedlings and allowing time to heal graft wounds prior to spring transplanting or double cropping is suitable for wheat–cotton intercropping to prevent late or early chilling damage associated with seed sowing or conventional transplanting of susceptible seedlings. Furthermore, the rapid and consistent wound healing in seedling grafts along with lateral shoot formation occurring in two of four grafting approaches make them a suitable approach to investigate possible genetic and epigenetic movement between scions and rootstocks, especially across species.

Does split nitrogen application increase garlic yield and quality?

Nitrogen (N) fertilization is essential for obtaining high garlic yields and satisfying commercial requirements for bulb diameter. However, excess nitrogen may favor the development of lateral shoots. This study aimed to examine the effect of different N application strategies on garlic yield and quality. The experiment was conducted in the field using garlic cv. Chonan and four N fertilization strategies (T1, N fertilizer applied at 15-day intervals; T2, N fertilizer applied before and after clove differentiation; T3, N fertilizer applied before clove differentiation; and T4, N fertilizer applied after clove differentiation). All treatments received the same N rate (210 kg ha-1). A single N application before clove differentiation (T3) favored lateral shoot growth, resulting in the highest incidence of this defect (11.66%). The other treatments did not differ in lateral shoot incidence. Four classes (3–6) of bulb diameter were observed, with treatments ranked in decreasing order as T2 > T1 > T3 > T4. There were no significant differences in garlic yield between single N application treatments (T3 and T4). However, garlic yield differed by 73% between T1 (13,329 kg ha-1) and T4 (7,679 kg ha-1), by 55.31% between T2 (11,927 kg ha-1) and T4, and by 36% between T1 and T3 (9,783 kg ha-1). These results indicate that two N fertilization strategies can be adopted in high-quality garlic production: fortnightly N fertilization or split N application before and after clove differentiation. A single N application is not recommended, regardless of application timing, as it promotes lateral shoot growth and reduces garlic quality and yield.

Spatial Relationships of Soil Physical Attributes with Yield and Lateral Shoot Growth of Garlic

Some compaction states cause changes in soil structure, resulting in increased soil density and soil resistance to penetration (RP). The objective of this study was: a) to analyze the variability of the studied attributes of the plant and the soil; b) define the linear and spatial correlations between plant and soil attributes; and c) to identify the best attributes that correlate spatially with garlic yield (GY) and lateral shoot growth (LSG) for the elaboration of spatial variability maps. The attributes evaluated were GY, apparent soil electrical conductivity (EC), mechanical resistance to penetration (MRP), soil volumetric moisture (SVM), plant water potential (WP), and LSG. The reach values of spatial dependence to be considered in future studies using the same attributes should be between 8 m for apparent soil EC and 23 m for RP. From a spatial point of view, garlic LSG could be estimated by indirect cokriging with soil RP. Values greater than 3000 kPa of soil RP indicated the sites with the lowest GYs.

Spatial Analysis and Mapping of the Effect of Irrigation and Nitrogen Application on Lateral Shoot Growing of Garlic

The objective of this study was to evaluate whether the spatial variability of plant production components and the use of an irrigation and fertirrigation management system with controlled deficit affect the yield and incidence of garlic lateral shoot growing (LSG). An analysis of these data through statistical and geostatistical techniques made it possible to verify that the increase in yield is directly related to the height and diameter of the bulb and that the lateral shoot growing is directly related to the increase in yield. Lower water depths and lower nitrogen doses applied during clove differentiation imply a lower incidence of LSG, whereas increased irrigation and fertigation with nitrogen results in lower bulb volumes.

Structural Integrity of Vascular System in Branching Units of Coniferous Shoot

In conifers with spiral phyllotaxis, two numbers: one of the vascular sympodia and the second of cortical resin canals, define the shoot anatomic diameter. This in turn reflects the size and vigor of the apical meristem. Both numbers belong to the mathematical series, associated with the shoot phyllotactic pattern. The number of canals is one step lower in a series than the number of sympodia. The first one, easier to determine, automatically defines the second. Using this protocol and screening the large number of branching shoots of selected conifers, we have discovered strong correlation between orientation of vascular sympodia in the lateral and supporting branches. There was no such correlation with regard to the chiral configurations of phyllotaxis. This finding reveals the presence of special phyllotactic compensation in the case of differences in anatomic diameter of the parental and lateral shoot under the imperative of maintaining the sympodia orientation within one branching unit. Phyllotaxis of the axillary apex is evidently not established at random but adapted to the condition of the subtending axis. The monopodial, regularly branching shoot of conifers is an attractive example of biological system, which is not a sum of independent, iteratively formed units. Rather, it appears to be an entity organized on hierarchically higher level, which emerges from coordination of developmental processes in a population of the units.