Morphometric relationships and their contribution to biomass and cannabinoid yield in hybrids of hemp (Cannabis sativa)

The breeding of hybrid cultivars of hemp (Cannabis sativa L.) is not well described, especially the segregation and inheritance of traits that are important for yield. A total of 23 families were produced from genetically diverse parents to investigate the inheritance of morphological traits and their association with biomass accumulation and cannabinoid yield. In addition, a novel classification method for canopy architecture was developed. The strong linear relationship between wet and dry biomass provided an accurate estimate of final dry stripped floral biomass. Of all field and aerial measurements, basal stem diameter was determined to be the single best selection criterion for final dry stripped floral biomass yield. Along with stem diameter, canopy architecture and stem growth predictors described the majority of the explainable variation of biomass yield. Within-family variance for morphological and cannabinoid measurements reflected the heterozygosity of the parents. While selfed populations suffered from inbreeding depression, hybrid development in hemp will require at least one inbred parent to achieve uniform growth and biomass yield. Nevertheless, floral phenology remains a confounding factor in selection because of its underlying influence on biomass production highlighting the need to understand the genetic basis for flowering time in the breeding of uniform cultivars.

Morphometric relationships and their contribution to biomass and cannabinoid yield in hybrids of hemp (Cannabis sativa)

The breeding of hybrid cultivars of hemp (Cannabis sativa L.) is not well described, especially the segregation and inheritance of traits that are important for yield. A total of 23 families were produced from genetically diverse parents to investigate the inheritance of morphological traits and their association with biomass accumulation and cannabinoid yield. In addition, a novel classification method for canopy architecture was developed. The strong linear relationship between wet and dry biomass provided an accurate estimate of final dry stripped floral biomass. Of all field and aerial measurements, basal stem diameter was determined to be the single best selection criterion for final dry stripped floral biomass yield. Along with stem diameter, canopy architecture and stem growth predictors described the majority of the explainable variation of biomass yield. Within-family variance for morphological and cannabinoid measurements reflected the heterozygosity of the parents. While selfed populations suffered from inbreeding depression, hybrid development in hemp will require at least one inbred parent to achieve uniform growth and biomass yield. Nevertheless, floral phenology remains a confounding factor in selection because of its underlying influence on biomass production highlighting the need to understand the genetic basis for flowering time in the breeding of uniform cultivars.

Daya Gabung dan Heterosis Galur Jagung (Zea mays L.) pada Karakter Hasil dan Komponen Hasil

Corn productivity can be improved using hybrid varieties. Evaluation of inbreds and hybrids were required to obtain information of general combining ability and specific combining ability. The objective of this research was to find out inbred combining ability and hybrids heterosis from crosses of 10 inbreds (5 inbreds from PT. Agri Makmur Pertiwi and 5 introduced inbreds) based on yield and yield components character. Diallel mating design using method 2 model 1 of Griffing model and the testing were conducted from January to August 2012. The tests using a randomized block design with three replications. PWM-1 (PT. Agri Makmur Pertiwi group) and PWI-5 (introduced group) have GCA better than other inbreds on grain yield, ear length, ear diameter, number of seed rows, shelling percentage and 1,000 seeds weight. Hybrids PWM-5 x PWM-1, PWI-5 x PWM-1 and PWI-5 x PWM-5 have a positive SCA values and also inbred parent have a positive GCA value. Intercrosses of introduced group had the high heterosis for all characters. PWI-4 x PWI-2 had highest SCA and heterobeltiosis for ear diameter and 1,000 seeds weight, and for number of seed rows was PWI-5 x PWI-2.<br /><br />Keywords: diallel cross, heterobeltiosis<br /><br />

Uso potencial de cruzas simples emparentadas de ciclo vegetativo intermedio para regiones subtropicales de México.

The maize breeding program and the Bajío Experimental Station, which belongs to the National Institute of Agriculture, Forestry and Livestock (INIFAP), located in the State of Guanajuato, Mexico, during 1994 and 1995, we evaluated yield trials with four types of genetic material: a. Original inbred lines wich are parents of superior single croses, under the release process. b. Modified parts coming from the cross of the original inbred parent, with a relative inbred line derived from the same germplasm source. c. Theoriginal single cross hybrids, and d. The modifield new crosses from the related parents. The results showed that the modified parents outyield in the original inbred lines, in some cases was of more than 300%. Moreover, some modified hybrids were statistically similar to the original single cross hybrids, as well as in some later commercial checks. The heterotic response, previously identified in specific single hybrids, was kept when we utilized modified parents with high yield. All this supported the idea that this kind of hybrids represent a large potential in the regions where the use of conventional single cross hybrids, is still limited.

Plant Regeneration from Leaf-derived Callus Cultures of Primrose (Primula vulgaris)

Efficient micropropagation of Primula species is important both for fundamental scientific studies and commercial applications. Primula vulgaris (Huds), along with other Primulaceae species, exhibits floral heteromorphy with two distinct forms of hermaphroditic flower. Studies to identify genes that control heteromorphic flower development require propagation of floral mutants, and efficient regeneration is a key requirement for plant transformation. Several species, including P. vulgaris cultivars and P. ×polyantha hybrids, are important horticultural crops in Europe, United States, and Japan and semidouble/double Primula varieties offer a high-end product. Vegetative propagation of sterile double forms, and as a means to increase numbers of inbred parent plants for F1 seed production is, however, slow. Micropropagation offers the most efficient way of increasing these varieties quickly and efficiently. To date, most Primula micropropagation protocols require explant material derived from in vitro grown seedlings or use floral parts as donor material with seasonal limitations. Therefore, an effective and efficient protocol was developed for in vitro regeneration of P. vulgaris via indirect organogenesis from adult leaf–derived explants. Exposure of leaf explants of P. vulgaris to media containing synthetic cytokinin, thidiazuron (TDZ), and auxin [1-naphthylacetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4-D)] resulted in undifferentiated cell proliferation and followed by differentiated growth as shoot organogenesis. Silver nitrate improved in vitro callus growth and increased shoot regeneration further, with up to 72% of explants producing shoots. Regenerated plants developed normally and produced normal fertile flowers within 7 months. The system was also successfully applied for the micropropagation of sterile double-flowered P. vulgaris ‘Sue Jervis’. The protocol reported here enables propagation of P. vulgaris without seasonal limitation or destruction of valuable parent donor material. The protocol, with further development, has the potential to underpin development of a transformation system for Primula, which would be of value in studies on flower development and disease resistance in laboratory grown plants.

The potential of hybrid potato for East-Africa

Potato is an important staple crop in East Africa. Most of the seed tubers are propagated in informal systems, whereby the tubers become deteriorated and contaminated, resulting in low crop yields. Potato breeding has not resulted in significantly improved varieties that overcome these constraints. Recently, true potato hybrid breeding technology has been developed, whereby diploid hybrids are generated by crossing between homozygous inbred parent lines. The first series of experimental hybrids were pre-screened in The Netherlands and ten representative hybrids were tested in East-Africa, whereby the yield of the best hybrid was 29 ton/ha. These results show the great potential of hybrid potato for East Africa.

A Soil Bioassay for Predicting the Risk of Spinach Fusarium wilt

The maritime Pacific Northwest is the only region of the United States suitable for production of spinach seed, a cool-season, daylength-sensitive crop. However, the acidic soils of this region are highly conducive to spinach Fusarium wilt, caused by Fusarium oxysporum f. sp. spinaciae. Rotations of at least 10 to 15 years between spinach seed crops are necessary to reduce the high risk of losses to this disease. The objectives of this study were to develop a greenhouse soil bioassay to assess the relative risk of Fusarium wilt in fields intended for spinach seed production, and to identify soil chemical and physical properties associated with conduciveness to this disease. Preliminary bioassays established a protocol for growing spinach plants in a greenhouse environment and inducing Fusarium wilt symptoms so that the bioassay can be completed in <2 months. Test soils with a range of Fusarium wilt inoculum potentials, and three spinach inbred parent lines (highly susceptible, moderately susceptible, and moderately resistant to Fusarium wilt) were used to evaluate sensitivity of the bioassay to different levels of risk of Fusarium wilt. Then, from 2010 to 2013, spinach seed growers and stakeholders submitted soil samples from 147 fields for evaluation with the bioassay. The fields were each under consideration for planting a spinach seed crop, yet the bioassay revealed a wide range in Fusarium wilt inoculum potential among soil samples. Differences in susceptibility to Fusarium wilt of the three inbred lines were key to detecting differences in wilt risk among soils. Visits to spinach seed crops planted in fields evaluated in the bioassay, as well as test plots of the three inbred lines planted in growers’ seed crops, confirmed the predictive value of the bioassay for Fusarium wilt risk. Correlation analyses for 23 soil properties revealed significant relationships of 15 soil properties with the Fusarium wilt potential of a soil, but the correlations were influenced significantly by susceptibility of the inbred line to Fusarium wilt (13, 10, and 8 soil properties correlated significantly with Fusarium wilt risk for the susceptible, moderate, and partially resistant inbreds, respectively). Multiple regression analyses identified different statistical models for prediction of Fusarium wilt risk depending on the spinach inbred line, but the best fitting model explained <34% of the variability in Fusarium wilt risk among 121 fields evaluated in the soil bioassay. Thus, no model was robust enough to replace the bioassay for the purpose of predicting Fusarium wilt risk.

Transfer of the Long-lived Postharvest Keeping Characteristic from a long-lived Inbred line of Antirrhinum majus (L.) to a Short-lived Line through the Inbred Backcross Method

In an effort to reduce chemical usage to prolong postharvest keeping time of cut flowers, a cross was made between a long-lived (vase life, 10.9 days) inbred line of Antirrhinum majus and a short-lived (vase life, 5.0 days) inbred line. The F1 hybrid was backcrossed to the short-lived parent. Sixty plants of the BC1 generation were carried on through three generations of selfing by single-seed descent. Eight replications each of 60 BC1S3 families, the parents, and the F1 hybrid were grown in the greenhouse, harvested with 40-cm stems when five florets opened, and placed in distilled water for vase life evaluation. Stems were discarded when 50% of the florets on a spike wilted, browned, or dried. Three families proved not significantly different from the long-lived inbred parent. Results indicate that inbred backcross breeding shows potential to increase the postharvest keeping time of short-lived Antirrhinum majus inbred lines.

ABNORMAL SEGREGATION FOR MORPHOLOGICAL MARKER GENES IN PROGENIES OF TISSUE CULTURE-DERIVED REGENERANTS OF HETEROZYGOUS TOMATO HYBRIDS

Heterozygous multiple marker genetic stocks were synthesized by crossing three multiple genetic marker stocks to a common inbred parent PU812. The four parents and 3 F1's were cultured to obtain regenerants from leaf discs. Fifty four regenerants were derived from 3 F1's and 12 from the 4 parents, Among the regenerants, 16 plants were identified as tetraploid (24.2%); low fertility was usually associated with tetraploidy, however there were a few exceptions.Selfed seeds, identified by cluster number, were harvested from sexual F1's and R0 plants for F2 progeny tests for the known marker genes. While there were no abnormal segregations for marker genes in the sexual progenies, 13 of 46 progenies from tissue culture derived regenerants showed significant deviations from expected normal segregations for a number of markers. Two of the abnormal progenies were identified as tetraploids by root-tip examinations; segregation ratios fit duplex random chromatid segregation for gene a on chromosome 11 and random chromosome segregation for gene c on chromosome 6. The cams of abnormal segregations in other progenies remain unknown. Results suggest that unknown genetic events arising during tissue culture may distort segregations for marker genes in the subsequent sexual progeny of tissue culture regenerants.