Modified hydroponics and phenolic foam as technological innovations in the production of coffee seedlings from cuttings

Brazilian coffee production represents an important activity in the country’s agricultural sector and, for this reason, it requires innovative technologies for the production of seedlings, which is one of the most important inputs in crop implantation. Thus, plant cloning by cutting, mineral nutrition via modified hydroponics and the use of alternative substrates appear as technological innovations for seedling production. This study evaluated the production of clonal coffee seedlings in a modified hydroponic system in comparison to the conventional climate-controlled greenhouse system, using vermiculite and phenolic foam as alternative substrates. At the end of the experiment, the seedlings were analyzed for growth (height, stem diameter, number of total leaves, leaf area, root area, shoot and root dry matter) and physiological (chlorophyll content and stomatal conductance) characteristics. For the statistical analysis, a completely randomized design was used in a factorial scheme 2 (types of substrate) x 2 (cultivation systems) with six replications and ten plants per plot. The innovative modified hydroponic system leads to a greater growth of coffee seedlings produced by cuttings in tubes with vermiculite compared to those produced in conventional systems. The substrate phenolic foam can be used alternatively in the air-conditioned greenhouse system. However, in the modified hydroponic system, it is not indicated, as it causes total seedling mortality.

Interrelationship Among Seed Quality Parameters and Fungi Associated with Seeds of Cotton (Gossypium Hirsutum L.)

A total of twenty nine species of fungi namely Aspergillus aculeatus Lizuka, A. flavus Link, A. fumigatus Fresenius, A. niger Van Tiegh, A. nidulans Eidam, A. subramanianii Visagie, Frisvad & Samson, A. tamariiKita G., A. toxicarius Murak, A. wentii Wehmer, Curvularial unata (Wakker) Boedijn, Colletotrichum gloeosporioides (Penz.) Sacc., C. gossypii Southw., Chaetomium globosum Kunze., Fusarium moniliforme J. Shelden, F. nivale (Fr.) Sorauer, F. oxysporum Schlechtendal, F. fujikuroi Nirenberg, F. solani(Mart.) Sacc., Lasiodiplodiatheobromae (Pat.) Griffon & Maubl., Meyerozyma guilliermondii (Wick.) Kurtzman & M. Suzuki., Mucor sp. P. Micheli ex L., Penicillium aculeatum Raper& Fennell, Penicillium citrinum Thom, Rhizoctonia solani Khun., Rhizopus stolonifer (Ehrenb.) Vuill., Rhizopus oryzae Went & Prins. Geerl., Rhizo mucor sp. Luce t & Costantin, Syncephalastrum racemosum Cohn and Trichoderma viride Pers. were found to be associated with the seeds of 14 varieties viz. CB-1 to CB-14 of cotton. Seed quality analysis showed that percentage of pure seeds, germination, moisture, seedling mortality and associated fungi with different varieties of cotton seeds varies from 97.08-99.92%, 80-93%, 10-11.3%, 16.05-50.30% and 24-78.0% respectively. Present study deals with estimation of interrelationship between some quality factors through correlation and regression analysis are important for the assessment of seed quality. There were negative correlations between seedling mortality and purity percentage and between germination rate and fungus frequency. On the other hand, positive correlations were found between germination rate and purity percentage, between seedling mortality and fungus frequency, between purity percentage and fungus frequency, between germination rate and seed moisture and between fungus frequency and seed moisture. CB 8 was superior from the other cotton variety as it showed higher physical purity of seed (98.41%), higher seed germination (92%), lower fungal incidence (24%) and lower mortality of seedling (23.91%). Bioresearch Commu. 8(1): 1061-1067, 2022 (January)

Direct Aulacaspis yasumatsui Infestation of Pre-Harvest Cycas Seeds Reduces Germination and Performance of Seedlings

The invasion of numerous countries by the armored scale Aulacaspis yasumatsui Takagi has caused widespread mortality of host Cycas species. Few studies have looked at reproductive biology responses of host plants to the herbivore. This study was conducted to determine the influence of direct Cycas seed integument infestation of A. yasumatsui on germination and seedling performance. An observational study in a Tinian ex situ Cycas micronesica K.D. Hill garden revealed that germination percentage was reduced two-thirds by heavy pre-harvest integument infestation, and more than half of the seedlings from infested seeds died in the nursery. Multi-year mortality of plants was six times greater for plants from habitats with infested seeds than for plants from minimally infested habitats. Stem height of nine-year-old plants from habitats with infested seeds was 64% of that of plants from habitats with un-infested seeds. A controlled study in a Philippine ex situ C. micronesica and Cycas edentata de Laub. garden corroborated these findings. Germination of infested seeds was about 30% of that for un-infested seeds. Seedling mortality in the nursery following experimental infestation of seed integuments with A. yasumatsui during seed maturation was about 50%, but was minimal for seedlings from un-infested seeds. These results indicate that limitations in regeneration and recruitment of host Cycas plants following A. yasumatsui herbivory may be partly due to the influence of direct seed infestations. Conservationists may use this new knowledge to improve in situ seed selection criteria and use prophylactic treatments to ensure lack of integument infestations for ex situ gardens.

QTL mapping for low temperature germination in rapeseed

Rapeseed, a major oil crop in the world, is easily affected by low-temperature stress. A low temperature delays seed germination and increases seedling mortality, adversely affecting rapeseed growth and production. In the present study, a tolerant cultivar (Huyou21) was crossed with a susceptible genotype (3429) to develop a mapping population consisting of 574 F2 progenies and elucidate the genetic mechanisms of seed germination under low temperatures. Two quantitative trait loci (QTL) for low-temperature germination (LTG) were detected, one on chromosome A09 (named qLTGA9-1) and the other on chromosome C01 (named qLTGC1-1), using the QTL-seq approach and confirmed via linkage analysis in the mapping population. Further, qLTGA9-1 was mapped to a 341.86 kb interval between the SSR markers Nys9A212 and Nys9A215. In this region, 69 genes including six specific genes with moderate or high effect function variants were identified based on the Ningyou7 genome sequence. Meanwhile, qLTGC1-1 was mapped onto a 1.31 Mb interval between SSR markers Nys1C96 and Nys1C117. In this region, 133 genes including five specific genes with moderate effect function variants were identified. These specific genes within the two QTL could be used for further studies on cold tolerance and as targets in rapeseed breeding programs.

Effects of overstory tree density, site preparation and ground vegetation on natural Scots pine seedling emergence and survival in northern boreal pine forests

Natural regeneration is commonly used forest regeneration method in Northern Finland. It is not known however, what would be the optimal overstory density and ground vegetation composition for seedling emergence and survival, and if site preparation is needed to accompany overstory density manipulation. We studied the effects of overstory density (unthinned control and thinning to 50, 150 and 250 trees ha-1) and ground vegetation removal (mechanical site preparation with disc trenching) on the number of naturally germinated pine seedlings and survival of individual seedlings during 8-11 years. Bare mineral soil was a superior seedbed compared to intact vegetation cover, even though also mortality rate was high on mineral soil. Greater cover of lingonberry, crowberry and slash had a negative effect on seedling number. Seedling mortality was initially high (60% died during the first two years) but decreased throughout the first five years. The mineral soil in the elevated part of disc trencher track showed twice the survival rate in the bottom part of the track. High coverage of small haired mosses was associated with poorer seedling survival. An overstory density of 50-150 trees ha-1 with site preparation seems to be an efficient treatment to promote regeneration under these circumstances.

Chitosan for suppression of fusarium wilt and plant growth promotion of brinjal

Chitosan is a biodegradable natural compound that has a great potentiality in agriculture for controlling plant diseases. An attempt was made to control Fusarium wilt caused by Fusarium oxysporum f. sp. melongenae under inoculated field condition and increase the growth and yield of brinjal by chitosan. Before setting the experiments in the field, preliminary laboratory experiments were carried out to select virulent isolate and effective dose of chitosan against the mycelial growth of the selected pathogen. F. oxysporum f. sp. melongenae isolate F-1 was found to be the most virulent on brinjal in pathogenicity test. Chitosan @ 1.0% concentration was appeared to be the highest inhibitory to the test pathogen at in vitro condition. Additionally, seed treatment with 1.0% chitosan for 12 hrs resulted in the highest increased in germination and seedling growth of brinjal. The field experiment was conducted following Randomized Complete Block Design (RCBD) with four treatments. No treatment was given in T1, the pathogen was inoculated in T2 and seed treatment and soil amendment with 1.0% chitosan was done in T3 and T4, respectively, in test pathogen inoculated condition. Application of 1.0% chitosan as a seed treatment (T3) or soil amendment (T4) significantly reduced pre- and post-emergence seedling mortality, incidence and severity of Fusarium wilt as well as enhanced germination percentage, plant growth and yield of brinjal. On the contrary, pre-emergence and post-emergence seedling mortality, disease incidence and severity of Fusarium wilt were highest in treatment T2 where the soil was inoculated with pathogen without chitosan. Therefore, chitosan could be used against this vascular disease as an alternative to inorganic fungicides and augment yield.

Effect of PEG Induced Drought Stress on Seed Germination and Seedling Growth of Greengram Genotypes

Greengram (Vigna radiata L. Wilczek) is the third most important pulse crop and drought is the most severe constraint to greengram growth and productivity. The present study was conducted to identify the drought tolerant greengram genotypes. Four greengram varieties used for standarization of drought stress using Polyethyleneglycol (PEG) 6000. The effect of water stress caused by different concentration of PEG 6000 are control (0 MPa), -0.4MPa, -0.5 MPa, -0.6MPa and -0.7 MPa. Increasing PEG concentration decrease the germination percentage, root length, shoot length, fresh weigh and dry weight of seedlings. At -0.5 MPa shows 50% seedling mortality , So control and -0.5 MPa level of drought stress was used for screening the greengram genotypes. Under PEG induced drought situations, parameters such as germination percentage, growth indices and proline content were recorded in all greengram genotypes. Compared to control, PEG induced drought stress (-0.5MPa) decrease all these parameters studied, where as drought has increased the proline content in all greengram genotypes screened. Among the greengram genotypes VGG17019 and VGG17004 posses higher germination percentage, GSI and proline content indicates high level of tolerance to drought stress.

QTLs Detection for Low-Temperature Germination in Rapeseed by QTL-seq and Linkage Mapping Approach

Rapeseed is a major oil crop in the world, which is easily affected by low-temperature stress. Low-temperature delays seed germination and increases seedling mortality that adversely affects rapeseed growth and production. To understand the genetic mechanisms of seed germination under low-temperature in rapeseed, we crossed a tolerant cultivar with a susceptible genotype to develop a mapping population of 574 F2 progenies. Two quantitative trait loci (QTLs) for low-temperature germination (LTG) were detected on chromosome A09 (named qLTGA9-1) and C01 (named qLTGC1-1) using QTL-seq method, and confirmed via linkage analysis in the mapping population. qLTGA9-1 was mapped to a 341.86-kb interval between SSR markers Nys9A212 and Nys9A215. In this region, 69 genes including six specific genes with moderate or high effect function variant were identified based on Ningyou7 genome sequence. qLTGC1-1 was mapped a 1.31-Mb interval between SSR markers Nys1C96 and Nys1C117. In this region, 133 genes including five specific genes with moderate effect function variant were identified based on Ningyou7 genome sequence. These specific genes within the two QTLs could be targets in rapeseed breeding programs and further studies for cold tolerance.

Forest Restoration at Berenty Reserve, Southern Madagascar: A Pilot Study of Tree Growth Following the Framework Species Method

Forest conservation and restoration are urgently needed to preserve key resources for the endemic fauna of dry southern Madagascar. This is a priority in the shrinking, seasonally dry forest of Berenty, a private reserve in Southern Madagascar. However, to provide a basis for forest restoration, a study of tree growth and regeneration in this unique biome is essential. A three-year planting program of native and endemic species was initiated in 2016. Three trial plots were established in forest gaps, with varying microclimates and soil conditions: one on the riverside, one in the mid-forest and the third in a degraded dryland area. We planted 1297 seedlings of 24 native tree species with plantings spaced at 1 m and 1.5 m and measured their height and stem diameters and recorded seedling mortality. We also recorded plant recruitment on the plots from the nearby forest. The main findings were that growth was best on the mid-forest plot planted at 1 m. Seedling mortality was highest on the riverside plot for the 1 m seedlings and least in the mid-forest at both planting distances. Recruitment was highest in the mid-forest at both planting distances and high also at 1.5 m by the river. These results are intended to aid future forest restoration on the Reserve and may serve as a reference for restoration of other dry forests in Madagascar. Finally, since species identification is central to the project, we collected, prepared and catalogued tree specimens to form a reference collection in an herbarium under construction in a new Research Centre at the reserve.