VIR - Resistance of accessions to corn stem borer

N. I. Vavilov All-Russian Research Institute of Plant Industry (VIR), Bolshaya Morskaya Street 42, 190000 St. Petersburg, Russia Tel.: +7 812 314-4848; Fax.: +7 812 311-8762; e-mail: vir@glas.apc.org

Grigoryev, Sergey V. 1998. Survey of the VIR Cannabis collection I: Resistance of accessions to corn stem borer (Ostrinia nubilalis Hb.) Journal of the International Hemp Association 5(1): 72-74. The Cannabis germplasm collection of the N.I. Vavilov All-Russian Research Institute of Plant Industry (VIR) contains many accessions that are largely uncharacterized for their wide variety of economically valuable traits. The corn stem borer Ostrinia nubilalis Hb. infects the upper portions of hemp plants and causes the terminal inflorescence to break, spoils the stalk and prevents seed formation. Thus, identification of forms and varieties of Cannabis that are resistant to this species is one of the priorities for hemp production in Russia. As a first step in the characterization of the VIR collection, the resistance of various accessions to O. nubilalis was tested.

Introduction
        The Cannabis germplasm collection preserved at the N.I. Vavilov All-Russian Research Institute of Plant Industry (VIR) is a source of exceptionally rich genetic diversity. Founded in 1922, the Institute’s hemp collection was arranged under the direction of N.I. Vavilov and serves as a source of valuable initial breeding materials that can be used in plant improvement programs of varying orientations. These accessions have played a key role in the creation of the main hemp cultivars of the former USSR and present Russia, the Ukraine and modern Europe. Many of the accessions in the VIR collection are now lost in the country of origin.
        Knowledge of exact genealogies serves not only for organizing the VIR collection, but also as useful information for breeders. If the entire collection were characterized for its valuable traits, it would be possible to make a conclusion on the availability of a needed trait from the germplasm collection of VIR, as well as on the possibility to incorporate a combination of useful traits in newly bred hemp lines and cultivars. This would enable us not only to supply the world’s hemp breeding community with recommendations concerning valuable accessions, but also to specify which traits might be successfully inherited or easily combined in new genotypes.
        One of the most destructive pests of hemp is the corn stem borer moth (Ostrinia nubilalis Hb.), known in North America as the European corn borer. O. nubilalis ranges across the entire territory of Russia. The northern range is not limited by low winter temperatures, as O. nubilalis is resistant to winter frosts. The northern limit is determined by the total summer warmth and reaches to approximately 56° N latitude. It is known that for full completion of the life cycle (larva, pupa, moth) of O. nubilalis , 711 degree-days of effective temperature are required in Russia. The life cycle will be interrupted if the total degree days are insufficient (Shegolev 1941). The heaviest infections of O. nubilalis are detected in the low-lying and moist arable lands suitable for cultivation of hemp, along riverbanks in the European part of Russia. The heaviest damage is reported in the major hemp growing regions of Penza, Bryansk, Orel, Chuvashia and Kursk Provinces in Russia and also in the Sumy Province of the Ukraine. The pest completes one full life cycle annually in this zone.
        Damage may also be heavy in large corn growing areas in the foothills and plains of the Caucasus. Two incomplete generations of the pest are allowed by the combination of high summer temperatures and high air humidity in this area. Similar climatic conditions are also found in the far east of Russia, but the lack of rainfall and low air humidity inhibit the pest’s pupation and causes diapause of the caterpillars.
        O. nubilalis infects a wide variety of crops. According to Shegolev (1941), 40 plant families are affected in the USA and 47 species of cultivated plants and 101 species of weeds are afflicted by the pest within the former USSR. Besides hemp, the heaviest damage is reported in cultivated millet and hops. Moderate damage is reported on sunflower and potato crops in the arable lands of central Russia that allow a full life cycle of the pest. Cotton may be afflicted in southern Russia. Artemisia vulgaris L. is the most commonly infected weed in Russia.
        Under low air humidity conditions, the major part of the damage is to the inflorescences of hemp. Young ovules and immature seeds are gnawed first by the caterpillars. The next larval generation causes dryness of the inflorescence and stalk through the action of young larvae gnawing out the inside tissues of plant stems. This leads to inflorescence damage and a breaking of hemp stalks in the field with consequent entanglement of plantings, which greatly hampers mechanized harvesting. Adult larvae of this pest survive winter as pupae inside the stalks of hemp plants, in harvested maize stalk residues or in weed stems. Heavy indirect losses in the afflicted crop result from various fungal diseases, such as Macrophomina phaseolina (McPartland 1996) and Fusarium sp. (Shegolev 1941). Damage at initial periods of vegetative growth leads to the death of the plant. O. nubilalis damage significantly reduces seed and long fiber yields up to fifty percent and also reduces fiber quality.

Methods and materials
Field tests of different cultivars, performed by Virovets and Lepskaya (1983) in the Ukraine, were used for analysis of the resistance of VIR collection accessions of Cannabis to O. nubilalis on a naturally infected background. The original research did not include the VIR accession numbers and therefore the resistance data was of little use to plant breeders. The data of Virovets and Lepskaya (1983) was re-evaluated to reflect VIR collection numbers and to include accessions of moderate, as well as high, resistance.

**Table 1.** Results of resistance testing the VIR *Cannabis* accessions to corn borers (*O. nubilalis*). Adapted from Virovets and Lepskaya (1983).
VIR Cat. No.	Avg. % damage	Origin



High Resistance Category: 0.00-4.50% infestation

not VIR	.00	Ukraine, ‘Southern Monoecious Sozrevayushchaya 27’ (USO-27)
not VIR	.00	Ukraine, ‘Southern Monoecious Sozrevayushchaya 25’ (USO-25)
k-465	.00	Turkey, local
k-486	.00	Yugoslavia, local
k-209	.00	France, ‘Chenevis’
k-8	.00	Yugoslavia, Domaca Province
k-13	.00	Yugoslavia, Domaca Prov. BR1
k-282	.00	Italy, North, ‘Carmagnola’
k-172	1.30	Hungary, ‘Fertodi’
k-508	1.30	Russia, Krasnodarskaya 56
k-128	1.30	Ukraine, Transcarpathia, Rakhovsky Reg.
k-122	1.30	Ukraine, Transcarpathia
k-132	1.30	Ukraine, Transcarpathia, Irshavsky Reg.
k-311	1.30	Ukraine, Glukhov, ‘Southern Cherkaskaya’
k-497	1.61	Ukraine, ‘Southern Sozrevajushaya 22’ (USO-22))
k-550	1.70	Ukraine, Southern Monoecious Sozrevayushchaya 24 (YUS-8 X YUSO-1) X (USO-24)
k-510	1.97	Ukraine, Dnepropterov, ‘Dnepropterovskaya 4’
k-142	2.00	Russia, Novosibirsk
k-503	2.12	Ukraine, Southern Monoecious Sozrevayushchaya 21 (USO-21)
k-540	2.40	Ukraine, ‘Southern Odnovremenno Sozrevayushchaya 29’ (USO-29)
k-433	2.70	Russia, Krasnodar, ‘Krasnodarskaya 35’
k-500	2.80	Ukraine, ‘Southern Monoecious Sozrevayushchaya 16’ (USO-16)
k-506	3.03	Ukraine, Southern Monoecious Sozrevayushchaya 25 (YUS-22 X YUSO-1) (USO-25)
k-429	3.26	Ukraine, Glukhov, ‘Southern Odnovremenno Sozrevayushch-1’ (YUSO-1)
k-389	3.30	Russia, Krasnodar, Dikaya
k-501	3.50	Ukraine, ‘Southern Monoecious Sozrevayushchaya 19’ (USO-19)
k-504	3.70	Ukraine, Southern Monoecious Sozrevayushchaya 23 (USO-23)
k-541	3.70	Ukraine, ‘Southern Odnovremenno Sozrevayushchaya 31’ (USO-31)
k494	3.80	Ukraine, ‘Southern Sozrevajushaya 8’ (YUS-8)
k-246	4.00	Germany, Bernburg 114199
k-6	4.00	Yugoslavia, ‘Bolonska’ (from Italy)
k-286	4.00	Ukraine, Dnepropetrovsk Reg., local
k-362	4.00	Russia, Udmurt, local
k-391	4.00	Ukraine, Glukhov, ‘Yuznaya Sozrevajucaya 6’ (YUS-6)
k-75	4.40	Russia, ‘Staro-Oskolskii Uluchshennyi’ (SOU)
k-460	4.50	Ukraine, Glukhov, ‘Southern Sozrevajucaya 4’ (YUSO-4)

Moderate Resistance Category: 4.60-8.00% infestation

k-520	4.83	Ukraine, ‘Southern Monoecious Sozrevayushchaya 28’ (YUSO-28)
k-51	5.30	United States, local
k-481	5.30	Hungary, ‘Uniko B’
k-560	5.75	Ukraine, ‘Dneprovskaya 1’ hybrid
k-461	6.45	Ukraine, Glukhov, ‘Southern Sozrevajucaya 9’ (YUS-9)
not VIR	6.55	Ukraine, ‘Southern Monoecious Sozrevayushchaya 26’ (USO-26)
k-519	6.85	Ukraine, ‘Southern Monoecious Sozrevayushchaya 27’ (YUSO-27)
k-458	6.97	Ukraine, ‘Glukhovskaya 10’
not VIR	7.00	Ukraine, ‘Southern Monoecious Sozrevayushchaya 30’ (USO-30)
k-289	7.00	Ukraine, Kirovograd, local
k-493	7.55	Ukraine, Glukhov, ‘Glukhovskaya 10’ Yellow Stem
k-496	7.66	Ukraine, ‘Southern Sozrevajushaya 12’ (USO-12)
k-499	7.77	Ukraine, ‘Southern Monoecious Sozrevayushchaya 14’ (USO-14)
k-290	8.00	Ukraine, Dnepropetrovsk Reg., local


(95 Percent LSD Intervals = 4.6%)

Results
The most resistant accessions, ranging from 0.0% to 4.5% infestation, are listed in Table 1.
The relationship between the resistance of the studied hemp accessions to O. nubilalis and the density of plantings in the field was also studied. The most severe incidences of infestation were observed in sparse hemp plantings at 500,000 plants per hectare with a row spacing of 45 cm (Table 2).

Conclusions
The varieties and accessions identified as having apparent resistance to infestation by O. nubilalis are from diverse origins. Cultivars currently in production, such as ‘USO-14’ and ‘USO-16’, may be utilized immediately in hemp production and the remainder of resistant accessions may be useful for breeding purposes (Table 1). Our results are somewhat different from those of Virovets and Lepskaya (1983). However, we reached common conclusions concerning the most resistant accessions (Table 1). We also identified moderately resistant varieties in Table 1.
The lowest incidence of infestation was observed in dense hemp plantings when plant density is 4 to 5 million plants per hectare with a row spacing of 15 cm (damage level 1).

Field density	Row spacing	Level of damage	Percent of infected plants



plants/ha	cm
4-5 million	15	1	1.08
4-5 million	20	4	3.45
3 million	15	2	4.88
500,000	45	3	16.36


(95 Percent LSD Intervals