EVALUATION OF ROMANIAN APPLE CULTIVARS IN LATVIA

Commercial apple growing in Latvia feels some lack of climate adapted modern cultivars. Development of fruits and trees is limited by active growth period (temperatures over 10 °C) of 135-150 days and active temperature sum of 1700-2100 °C. Winter hardiness also is essential, as temperatures below −30°C occur each 10 years, and winter thaws are frequent. Annual precipitation 692 mm favours development of fungal diseases. In 2016, a trial of four Romanian apple cultivars resistant to scab - ‘Aura’, ‘Ciprian’, ‘Jonaprim’ and ‘Romus 3’ was established in Latvia. Trees were grafted on dwarfing rootstock B.396 and planted as 1-year old whips in 3 replications with 2-3 trees in each replication, and trained as slender spindle. Commercial cultivars ‘Auksis’ (midseason) and ‘Ligol’ (late) were used as controls. Most trees of all cultivars in the 2nd year (2017) developed a well branched frame, from 37.5% trees of ‘Ciprian’ to 90% trees of ‘Jonaprim’. The first fruits were harvested in 2017, and commercially significant yield was achieved in 2018, except ‘Jonaprim’, which had the slowest yield increase. By the sum of yield in 2017-2021 ‘Aura’ and ‘Jonaprim’ surpassed commercial cultivar ’Auksis’, but were less productive than ‘Ligol’. Only slightly lower summary yield was obtained from ‘Ciprian’, while ‘Romus 3’ showed the lowest productivity and strong premature fruit drop. Very good taste panel results were obtained for ‘Aura’ and ‘Ciprian’, 7 to 8 points in average. Their fruits also kept well, to 5 months in common storage at 2 ±1oC. Fruits of the other two cultivars were too small and had mediocre or poor taste. The weather conditions in the trial years allowed to test susceptibility to spring frosts and drought. All cultivars showed good tree health after over-wintering. ‘Jonaprim’ and ‘Auksis’ in 2019 had the highest spring frost injury, 60-70% of fruits, while least injured were ‘Aura’ (21.5%) and ‘Ciprian’ (27.7%). Extreme drought in summer of 2021 led to low average fruit mass of all cultivars including the normally large fruited ‘Ligol’ (120-130 g), while in other years ‘Aura’ had fruits over 180 g, very attractive yellow with red stripes. Fruits of ‘Ciprian’ also had good size, but in some years too dark over-colour. ‘Aura’ and ‘Ciprian’ showed good adaptation to the climate of Latvia and can be recommended for wider trials at farms.

Chemical Composition of Gmelina arborea: A Review

Gmelina arborea is a fast-growing tree, which grows on different localities and prefers moist fertile valleys with 750–4500 mm rainfall. It does not thrive on ill-drained soils and remains stunted on dry, sandy or poor soils; drought also reduces it to a shrubby form. The tree attains moderate to large heights of up to 30 m, with a girth of 1.2 to 4 m. It has a chlorophyll layer just under the outer bark, which is pale yellow on the outside and white inside.Gmelina arborea wood is pale yellow to cream-coloured or pinkish-buff when fresh, turning yellowish brown on exposure and is soft to moderately hard, light to moderately heavy, lustrous when fresh, usually straight to irregular or rarely wavy grained and medium course textured. Flowering takes place during February to April when the tree is more or less leafless whereas fruiting starts from May onwards up to June. The fruit is up to 2.5 cm long, smooth, dark green, turning yellow when ripe and has a fruity smell. The fruit is edible and has a bitter-sweet taste.4 This tree is commonly planted as a garden and an avenue tree; growing in villages along agricultural land and on village community lands and wastelands. It is light demander, tolerant of excessive drought, but moderately frost hardy. It has good capacity to recover from frost injury. Gamhar trees coppices very well with vigorous growth. Saplings and young plants need protection from deer and cattle. Gmelina arborea grows naturally throughout India, Myanmar, Thailand, Laos, Cambodia, Vietnam and in southern provinces of China

Cold-triggered induction of ROS- and raffinose-related metabolism in freezing-sensitive taproot tissue of sugar beet

Sugar beet (Beta vulgaris subsp. vulgaris) is the exclusive source of sugar in the form of sucrose in temperate climate zones. There, sugar beet is grown as an annual crop from spring to autumn because of the damaging effect of freezing temperatures to taproot tissue. Natural and breeded varieties display variance in the degree of tolerance to freezing temperatures and genotypes with elevated tolerance to freezing have been isolated. Here we compare initial responses to frost between genotypes with either low and high winter survival rates. The selected genotypes differed in the severity of frost injury. We combined transcriptomic and metabolite analyses of leaf- and taproot tissues from such genotypes to elucidate mechanisms of the early freezing response and to dissect genotype- and tissue-dependent responses. Freezing temperatures induced drastic downregulation of photosynthesis-related genes in leaves but upregulation of genes related to minor carbohydrate metabolism, particularly of genes involved in raffinose metabolism in both, leaf and taproot tissue. In agreement with this, it has been revealed that raffinose and the corresponding intermediates, inositol and galactinol, increased markedly in these tissues. We found that genotypes with improved tolerance to freezing, showed higher accumulation of raffinose in a defined interior region within the upper part of the taproot, the pith, representing the tissue most susceptible to freeze damages. This accumulation was accompanied by specific upregulation of raffinose synthesizing enzymes in taproots, suggesting a protective role for raffinose and its precursors for freezing damage in sugar beet.

JENIS DAN POPULASI BAKTERI ICE NUCLEATION ACTIVE PENYEBAB LUKA BEKU PADA DAUN JERUK KEPROK SOE DI DATARAN TINGGI MUTIS

Research on ice nucleation-active bacteria causes frost injury from tropic areas has not been widely publicized. The purpose of this study was to determine the population of Ice Nucleation-Active Bacteria on Soe tangerines leaves and the class of Ice Nucleation-Active bacteria based on Ice formation temperatures. The collecting of Soe tangerine leaves used the purpose sampling method. Leaves with frost blotches were collected from three stages at altitudes of 1500, 1800, and 2000 meters above sea level (m asl). Bacterial isolation was carried out by the spread plate method on Nutrien Agar 2,5 % glycerol (NAG) media. Ice Nucleation activity was determined by the tube nucleation test method. Estimation of INA bacterial population was conducted by the multiple-tube nucleation test with Thomas series .3.3.3. The result showed that the highest INA bacterial population was 6.9x104 which was found in leaves samples collected from stations 1800 and 2000 m asl, and the lowest population i.e. 5,4x103 on leaf samples from station 1500 m asl. Based on the temperature of ice formation, it was known that INA bacteria that attack the Soe tangerines leaves Mutis plateau are the INA bacteria class B and C.

Young Field-grown Kiwifruit Plants’ Response to Early Autumn Frost Injury in Texas

Two-year-old, field-grown golden kiwifruit (Actinidia chinensis) and fuzzy kiwifruit (Actinidia deliciosa) plants were evaluated for injury following an early freeze event of −4.1 °C on 14 Nov. 2018 in Burleson County, TX. Plant material included seven cultivars: one seed-propagated [Sungold™ (ZESY002)] and three cutting-propagated golden kiwifruit (AU Golden Dragon, AU Golden Sunshine, CK03), and one seed-propagated (Hayward) and two cutting-propagated fuzzy kiwifruit (AU Authur and AU Fitzgerald). Observations were made 5 weeks after the frost event. Base trunk diameter (BD) and maximum trunk diameter damaged (MDD) provided a reference of plant size and crude measurement of damage intensity, as evident by presence of water-soaked necrotic and/or dehydrated tissue following the removal of a thin slice of periderm, vascular cambium, phloem, and xylem. Percent of base diameter damaged (PBDD) was calculated as MDD divided by BD and provided an assessment of damage, unbiased by plant size. Percent of shoot damaged (PSD) was visually evaluated as the percentage of entire shoot system exhibiting damage. In addition, presence of basal damage (DB) and basal cracking (CB) were recorded. A strong cultivar response was observed for BD, MDD, PBDD, and PSD. Mean cultivar values for PSD ranged from 79% and 19% for AU Authur and Sungold™ seedlings, respectively, which represented extremes among cultivars. Fuzzy kiwifruit exhibited greater injury (PBDD, PSD, DB, and CB) as compared with golden kiwifruit cultivars. Basal damage and basal cracking proved unique to fuzzy kiwifruit, as DB ranged from 0% in Sungold™ seedlings to 100% in fuzzy kiwifruit ‘AU Authur’ and ‘AU Fitzgerald’. In spite of having greater vigor, golden kiwifruit plants sustained less injury. Method of propagation had no effect on injury. PBDD and PSD proved to be reliable field assays for documenting injury, based on their strong correlation value (r = 0.92). Greater relative autumn frost tolerance of golden kiwifruit over fuzzy kiwifruit cultivars is previously unreported.

Performance of frost protection structures on yield and post-harvest quality of organically grown winter dawn strawberry

Low tunnel protected cultivation of organically grown strawberry (winter dawn) was carried out to standardize the cladding material and the height of structure for enhancing the yield and post-harvest quality in Punjab North India. Three different design of low tunnels i.e. three different heights; 45 cm, 60 cm and 75 cm and three claddings; thin plastic film (50 microns), UV stabilised plastic sheet (200 microns) and non-woven film (20 GSM) were used in the trials. Microclimate parameters, soil moisture and soil temperature inside the installed structures were analyzed throughout the experiments. The maximum yield of crop, number of fruits (45), maximum weight (28g) was observed in the tunnel of size 45 cm with non-woven 20 GSM followed by UV 200 micron of 60 cm height and minimum values were observed in other structures and open. All the tunnels maintained favourable soil and canopy temperature for the growth of crop and it was observed that crop grown inside tunnels were protected from any kind of frost injury and exhibited better post-harvest quality than the strawberry grown in open.

A Methodological Approach to Determine Flower Bud Vulnerability to Low Temperatures for Deciduous Crops in Early Spring Using Degree Days

A common problem for decision makers in selecting frost control options is uncertainty about the level of injury that can be caused by low temperatures. During the past few years, the concept of lethal temperature (LT) at which 10% of the bud population dies (LT10) has been used as an index for evaluating the vulnerability of flower buds to low temperature conditions. This concept has shown to be a useful tool for frost control decision-making. However, the current methods used to obtain LT values assume no spatial or temporal variability, which results in a high level of uncertainty. The goal of this study was to develop an approach that decreases the uncertainty based on the known effects of temperature on bud vulnerability. A growth chamber experiment was conducted to determine flower bud vulnerability to low temperature as a function of temperature. The results from this study showed that thermal time expressed in degree days could explain changes in floral bud development and vulnerability to frost injury. According to our findings, LT10 is a fully acceptable index for determining flower bud vulnerability to low temperatures in orchard crops. Based on this information, we found that among the five apple and cherry cultivars analyzed, ‘Gala’ is the least vulnerable to low temperature because it starts at the beginning of spring with a high level of hardiness and increases its vulnerability at a low rate. The approach described in this article may enhance decision-making certainty associated with the timing and methods to increase air temperature in orchards during low-temperature events to avoid frost damage.

Inheritance pattern of cold tolerance in pigeonpea [Cajanus cajan(L.) Millsp.]

Among all the abiotic stresses, cold is one of the important factor limiting crop productivity. Medium and late maturing varieties cover most of the cultivated area of pigeonpea and therefore the chances of facing cold/frost are prominently high. Northern parts of the country are witnessing very low temperature during the last fort night of December and first fortnight of January, which is conducive for frost injury and the susceptible lines exhibit frost symptoms. Screening of 302 germplasm/lines of pigeonpea comprising of varieties and advance materials against frost injury during the years 2016-2018 facilitated to identify tolerant and susceptible lines. One hundred and forty one lines did not show any injury symptom, whereas 120 were classified under score 1 and 17 lines showed moderate symptoms to frost injury. A highly frost tolerant (insensitive) line ICP 10509 was crossed to susceptible (sensitive) line ICP 11182 to study the nature of frost injury and mode of inheritance. The F1 hybrid showed tolerance to frost injury with 1-2 leaves showing little symptom (score 0-1) indicating dominance of the trait. The F2 population segregated into tolerant (216 plants) and susceptible individuals (91 plants) fit well into expected ratio of 3(T): 1(S) (P value = 0.06027) signifying that frost tolerance (insensitivity) is controlled by a single dominant gene. The proposed hypothesis was verified by backcross populations; B1 (F1 x ICP 11182) segregating into 1(T):1(S) ratio (P value = 0.1237), whereas, all the plants in B2 (F1 x ICP 10509) generation exhibited tolerance to frost injury. The identification of a single gene exhibiting tolerance to frost injury may be useful for developing frost tolerant genotypes.