Assessment of weather effect on flower morphogenesis and fruit set in mango varieties in central India

A two-year field experiment was initiated in 2017-18 and 2018-19 years simultaneously to assess temperature on flower morphogenesis stages, flower sex ratio (hermaphrodite/staminate male flower) and fruit set in monoembryonic Langra and Amrapali varieties. Different dates of flower phenological stages viz., bud, panicle, bloom and flower initiation, pea, marble, egg, and maturity of fruits were recorded. The Langra variety exhibited bud initiation after mid December whereas Amrapali variety by the end of December. The range of mean maximum / minimum temperature as 26-31/10-12 °C promoted hermaphrodite flowers per panicle by 74 per cent in Langra variety, whereas range of 27-29/11-13 °C favored by 35 per cent in Amrapali variety. A positive and significant correlation between total number of flower / panicle and flower sex ratio in both the varieties suggested that higher temperature during initial flower phenologies improved number of hermaphrodite flowers. A mean minimum temperature for producing more number of hermaphrodite flower exhibited a range of 11-14 °C under central Indian conditions. Fruit set was maximum during pea stage and decline afterwards in marble and fruit maturity stages due to sudden rise in temperature at marble stage that caused in drop down of humidity thereby resulted in fruit drop in both the varieties.

An assessment of temporal variability in mast seeding of North American Pinaceae

Our overall objective is to synthesize mast-seeding data on North American Pinaceae to detect characteristic features of reproduction (i.e. development cycle length, serotiny, dispersal agents), and test for patterns in temporal variation based on weather variables. We use a large dataset ( n = 286 time series; mean length = 18.9 years) on crop sizes in four conifer genera ( Abies , Picea , Pinus , Tsuga ) collected between 1960 and 2014. Temporal variability in mast seeding (CVp) for 2 year genera ( Abies , Picea , Tsuga ) was higher than for Pinus (3 year), and serotinous species had lower CVp than non-serotinous species; there were no relationships of CVp with elevation or latitude. There was no difference in family-wide CVp across four tree regions of North America. Across all genera, July temperature differences between bud initiation and the prior year (Δ T ) was more strongly associated with reproduction than absolute temperature. Both CVp and Δ T remained steady over time, while absolute temperature increased by 0.09°C per decade. Our use of the Δ T model included a modification for Pinus , which initiates cone primordia 2 years before seedfall, as opposed to 1 year. These findings have implications for how mast-seeding patterns may change with future increases in temperature, and the adaptive benefits of mast seeding. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

Studies on the Effect of Different Plant Densities and Levels of CRF on Growth, Yield and Quality of Flowers of Statice (Limonium sinuatum L.)

A Field Experiment was conducted during Rabi season 2019-2020 at Experimental field, Department of Horticulture, Naini Agriculture Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj (U.P.), India. The experiment was Evaluated in a Factorial randomized block design (FRBD) with three replications and 12 treatments. Among the CRF of 6g recorded significantly higher growth parameters followed by CRF of 4g, 2g and control. Spacing of 45cm x 60cm had a considerable influence on the number of leaves and length of leaves. Whereas, plant height was significantly higher with a spacing of 15cm x 30cm at all the growth stages. In flowering parameters, Controlled-release Fertilizers and spacing had a significance influence on the flowering parameters of statice. CRF of 6g per plant obtained notably higher flowering parameters like length of flower stalk and day of flower bud initiation to the day of harvesting whereas, highest delay in flower stalk initiation was observed in Control. The closer spacing of 15cm x 30cm had considerable influence on days required to flower stalk initiation/appearance, length of flower stalk and day of flower bud initiation to the day of harvesting or flowering duration. The higher yield with superior quality of flowers obtained with CRF of 6g with wider spacing of 45cm x 60cm.

Effect of Organic and Inorganic Sources of Nutrients on Flowering of Hybrid Gerbera (Gerbera jamesonii B.) cv. Shimmer in Open Field Condition

The present investigation on Effect of organic and inorganic sources of nutrients on flowering of hybrid gerbera (Gerbera jamesonii B.) cv. Shimmer in open field condition was conducted at Biotechnology cum Tissue Culture Centre, OUAT Bhubaneswar during 2015-16 and 2016-17. The aim of the study was to find out suitable organic and inorganic sources of nutrients for cut flower production of gerbera in open field condition. There were eight treatment combinations consisting of 100% recommended dose of fertilizer (RDF), Vermicompost, 75% RDF, PSB, Azospirillum, Azotobacter and foliar spray of macro and micro elements. Application of 75% RDF (15:10:30 g NPK/10 plants) + Vermicompost (25 g/10 plants) + Azospirillum/ Azotobacter (20 g/10 plants) + PSB (20 g/10 plants) + macro and micro element spray recorded earlier flower bud initiation and flowering. The same treatments conducted to maximum length of flower stalk, thickness of flower stalk, flower diameter, number of flowers/plant and bloom life. It can be concluded that reduced dose of chemical fertilizer (75% RDF) along with application of vermicompost and biofertiizer can improve flower yield of gerbera in open field condition.

Overexpression of SHORT-ROOT2 transcription factor enhanced the outgrowth of mature axillary buds in poplar trees

Plant branching is usually prevented by an actively proliferating apex. In poplars, one GRAS family member, SHORT-ROOT2 (PtSHR2), was preferentially expressed in axillary buds (AXBs) and was inducible during bud maturation and activation. Overexpression of PtSHR2 (PtSHR2OE) in hybrid poplar impaired the apical dominance and simultaneously promoted the outgrowth of axillary branches below the maturation point (BMP), accompanied by regulated expression of genes critical for axillary meristem initiation and bud formation. Following a detained phenotypic characterization, we compared the IAA and trans-zeatin levels in apical shoots and AXBs of wild-type and PtSHR2OE trees, together with gene expression analyses and defoliation, decapitation, and hormone reapplication assays. PtSHR2OE AXBs contained a significantly lower ratio of auxin to cytokinin than wild-type AXBs, particularly in those below the BMP. Decapitation induced a faster bud burst in PtSHR2OE trees than in wild-type plants, and it could be strongly inhibited by exogenously applied auxin and cytokinin biosynthesis inhibitor, but only partially inhibited by N-1-naphthylphthalamic acid (NPA). An impaired basipetal auxin transport, rather than an insufficient auxin biosynthesis or auxin insensitivity, disturbed the local hormonal homeostasis in PtSHR2OE AXBs, which in turn enhanced the axillary bud initiation and promoted the bud release.

​​Habitat Manipulation: An Important Component of IPM in the Management of Webbing Caterpillar, Maruca vitrata (Geyer) in Pigeonpea

Background: Maruca vitrata is an economically important cryptic insect pest in pigeonpea. Caterpillar, the damaging stage hides in the webs thus escapes the contact with insecticides thus making an effective insecticide also ineffective. Hence, the role of some tall statured intercrops in the manipulation of pigeonpea crop environment for reducing the incidence of this webbing caterpillar was studied. Methods: Studies were conducted at NPRC, Vamban, Pudukottai dt., Tamil Nadu to study the effect of different intercrops in reducing the incidence of Maruca vitrata. During kharif 2016-17 and 2017-18, M. vitrata incidence was compared among the intercropping systems (pigeonpea with pearlmillet, sorghum and maize in 1:6 ratio) and sole pigeonpea crop. IPM modules were formulated in which botanical spray (NSKE 5% at bud initiation stage) and spray of recommended insecticide (indoxacarb 15.8 EC-0.7 ml/lt at flowering and 15 days later) were integrated with intercropping practice and tested for efficacy against this borer pest. Result: Intercropping of pigeonpea with pearlmillet was effective in managing the spotted pod borer. Coccinellids and spiders were more in intercropped pigeonpea than the sole pigeonpea crop. Synchronized flowering times of short duration pigeonpea and intercrops would have facilitated the transfer of natural enemies from intercrops to pigeonpea and this may be the one of the reasons for the lower insect population. IPM module I (pigeonpea intercropped with pearlmillet, NSKE and indoxacarb sprays) was effective in reducing the spotted pod borer damage. In IPM module I, yield of 770 kg/ha was obtained as against 550 kg/ha in sole pigeonpea crop. Among the IPM modules, high B:C ratio of 1:1.66 was recorded with IPM module I.

GRAS transcription factor LOSS OF AXILLARY MERISTEMS is essential for stamen and runner formation in wild strawberry

Axillary bud development is a major factor that impacts plant architecture. A runner is an elongated shoot that develops from axillary buds and is frequently used for clonal propagation of strawberry. However, the genetic control underlying runner production is largely unknown. Here, we identified and characterized loss of axillary meristems (lam), an EMS-induced mutant of the diploid woodland strawberry (Fragaria vesca) that lacked stamens in flowers and had reduced numbers of branch crowns and runners. The reduced branch crown and runner phenotypes were caused by a failure of axillary meristem initiation. The causative mutation of lam was located in FvH4_3g41310, which encodes a GRAS transcription factor, and was validated by a complementation test. lamCR mutants generated by CRISPR/Cas9 produced flowers without stamens and had fewer runners than the wild type. LAM was broadly expressed in meristematic tissues. Gibberellic acid (GA) application induced runner outgrowth from the remaining buds in lam, but failed to do so at the empty axils of lam. In contrast, treatment with the GA biosynthesis inhibitor paclobutrazol (PBZ) converted the runners into branch crowns. Moreover, genetic studies indicated that lam is epistatic to suppressor of runnerless (srl), a mutant of FveRGA1 in the gibberellic acid pathway, during runner formation. Our results demonstrate that LAM is required for stamen and runner formation and acts sequentially with GA from bud initiation to runner outgrowth, providing insights into the molecular regulation of these economically important organs in strawberry.

GENETIC DIVERSITY ANALYSIS OF COMMON BEAN (PHASEOLUS VULGARIS L.) COLLECTED FROM NORTH WEST HIMALAYA FOR AGRO-MORPHOLOGICAL TRAITS

Understanding of genetic diversity among the genotypes is the mainstay of plant breeding. The present study was carried out to determine genetic divergence among 59 common beans genotypes collected from North West Himalaya for nine agromorphological traits. The analysis of variance depicted significant variability among genotypes for all the traits under study indicating wide range of variability present in bean genotypes. The phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) was high for seed yield per plant followed by days to bud initiation. High heritability was also observed for all traits except pod length. Cluster analysis grouped bean genotypes into five distinct clusters. The genotypes under group II, III, V have more number of pods per plant, seeds per pod and single plant yield which can be utilized as potential donors for enhancing the yield of other genotypes in breeding programmes. Hence, the selection based on these yield contributing traits may helpful in future crop improvement programmes

Toward Systematic Understanding of Flower Bud Induction in Apple: A Multi-Omics Approach

The induction of flower buds in apple (Malus × domestica Borkh.) is tightly connected to biennial bearing, which is characterized by alternating years with high (ON) and low or no (OFF) crop loads. In order to study this irregular cropping behavior, spur buds from ON- and OFF-trees of the biennial-bearing cultivar ‘Fuji’ and the regular bearing cultivar ‘Gala’ were collected. First, the time of flower bud initiation was precisely determined for both cultivars by histological analysis. Moreover, for a systematic understanding of flower bud induction in apple, the physiological and molecular mechanisms within the bud tissue were evaluated over four weeks prior to flower bud initiation by employing a multi-omics approach, including RNA sequencing, proteomic and metabolic profiling. Gene and protein enrichment analysis detected physiological pathways promoting and inhibiting early flower bud development. Metabolic profiles from the cropping treatments revealed a greater abundance of thiamine, chlorogenic acid, and an adenine derivative in spur buds from OFF-trees, whereas tryptophan was more abundant in the buds collected from ON-trees. Cultivar comparison indicated that chlorogenic acid was more abundant in ‘Gala’ than in ‘Fuji’ spur buds, whereas the opposite effect was found for tryptophan. Genes controlling tryptophan biosynthesis were not affected by ON- and OFF-treatments, but genes assigned to the metabolism of tryptophan into indoleacetate were differentially expressed between cultivars and treatments. The multi-omics approach permitted analyzing complex plant metabolic processes involved in early flower bud development and more specifically presumably in flower bud induction by tracing some pathways from gene to product level.