Sugarcane Mosaic Virus Strain Research Articles

Registration of ‘CP 10‐1620’ sugarcane

Abstract‘CP 10‐1620’ (Reg. no. CV‐216, PI 693837) sugarcane (a complex hybrid of Saccharum spp.) was developed through cooperative research conducted by the USDA–ARS, the University of Florida, and the Florida Sugar Cane League, Inc. At the June 7, 2018, Florida Sugarcane Variety Committee Meeting, CP 10‐1620 was released to growers for mineral (sand) soils in Florida, and seed was available in September 2018. CP 10‐1620 was selected from a polycross of ‘CP 00‐1100’ × ‘CP 05‐1740’ (Cross no. X07‐1225) made at Canal Point, FL, in December 2007. Neither the female parent, CP 00‐1100, nor the male parent, CP 05‐1740, is a commercial cultivar. Cane yield of CP 10‐1620 on sand soils, averaged across 12 harvests through three crop cycles (plant cane, first ratoon, and second ratoon), was 11.0% higher (P < 0.05) than the combined mean of three checks, ‘CL 88‐4730’, ‘CP 96‐1252’, and ‘CPCL 97‐2730’, which are commercial checks for sand soils. The commercial recoverable sucrose for CP 10‐1620 was not significantly lower than the combined mean of the checks but the higher cane yield resulted in 8.4% higher (P < 0.05) sucrose yield than the combined mean of the checks. CP 10‐1620 was released because of its high cane yields on sand soils, and its acceptable levels of resistance to brown rust (caused by Puccinia melanocephala H. & P. Sydow), leaf scald (caused by Xanthomonas albilineans Ashby, Dowson), Sugarcane mosaic virus strain E (mosaic), smut (caused by Sporisorium scitamineum), Sugarcane yellow leaf virus, and ratoon stunt [caused by Leifsonia xyli subsp. xyli (Davis et al.) Evtushenko]. CP 10‐1620 was moderately susceptible to orange rust (caused by Puccinia kuehnii E. J. Butler), and it has high freeze tolerance. CP 10‐1620 tested positive for the Bru1 locus, which is an indicator of brown rust resistance.

Registration of ‘CP 13‐1954’ sugarcane for Florida organic soils

Abstract‘CP 13‐1954’ (Reg. no. CV‐218, PI 704104) sugarcane (Saccharum spp. hybrid) was developed through cooperative research conducted by the USDA–ARS, the University of Florida, and the Florida Sugar Cane League, Inc., and released to growers for organic (muck) soils in Florida in June 2020. The parentage of CP 13‐1954 is ‘CP 85‐1491’ × Poly 09‐24. Based on the results of three crops (plant cane, first ratoon, and second ratoon) in field trials conducted at five locations, CP 13‐1954 had higher cane yield (16.2%), sucrose yield (15.6%), and economic index (29.7%) at P < .05 compared with the reference cultivar, ‘CP 96‐1252’. CP 13‐1954 stalks are usually taller than the reference cultivar, ‘CP 00‐1101’, with small‐to‐medium diameter, and exhibits resistance to ratoon stunting disease, Sugarcane mosaic virus strain E, brown rust, orange rust, and smut and moderate resistance to leaf scald on muck soils in Florida. CP 13‐1954 has Bru1 locus that provides resistance against brown rust. CP 13‐1954 showed moderate cold tolerance among all the tested cultivars.

Registration of ‘CP 15‐2516’ sugarcane for organic soils in Florida

Abstract‘CP 15‐2516’ (Reg. no. CV‐215, PI 703029) sugarcane cultivar, a complex hybrid of Saccharum spp., was developed jointly by USDA‐ARS, the University of Florida, and the Florida Sugar Cane League. CP 15‐2516 was released in June 2022 for commercial cultivation on the Florida organic (muck) soils due to its high cane and sucrose yields, commercial recoverable sucrose (CRS), and economic index (EI). CP 15‐2516 originated from CPX13‐1630, a cross between a female parent (CP 95‐1039) and a male parent (‘CP 06‐2400’). CP 15‐2516 is resistant to brown rust, orange rust, and Sugarcane mosaic virus strain E. CP 15‐2516 harbors the Bru1 marker associated with brown rust resistance. CP 15‐2516 is moderately resistant to leaf scald and ratoon stunt disease, smut, and yellow leaf. Based on the results of three harvest cycles over five locations in Stage 4 on muck soils, cane and sucrose yields of CP 15‐2516 were 10.48% (181.31 Mg ha−1) and 11.49% (18.62 Mg ha−1) respectively, higher (P < .05) than those of the reference cultivar ‘CP 96‐1252’. Compared with CP 96‐1252, the EI of CP 15‐2516 was significantly (P < .05) higher by 15% (3233 ha−1). The mean cane fiber content of CP 15‐2516 was 138.7 kg Mg−1 and was 1% to 8% higher than the reference cultivars (‘CP 00‐1101’, CP 96‐1252, and ‘CPCL 05‐1201’). CP 15‐2516 flowers intermittently during January in Florida's climate. CP 15‐2516 has a better freeze tolerance than commercial reference cultivars CP 00‐1101 and CP 96‐1252. CP 15‐2516 is expected to positively contribute to the profitability and sustainability of the Florida sugarcane industry.

Registration of ‘CP 14‐1377’ sugarcane for organic soils in Florida

Abstract‘CP 14‐1377’ (Reg. no. CV‐211, PI 700115), a new sugarcane (a complex hybrid of Saccharum spp.) cultivar, was developed through cooperative research conducted by the USDA‐ARS, the University of Florida, and the Florida Sugar Cane League, Inc. CP 14‐1377 was selected from the polycross (X12‐1500) between CP 03‐1094 and Poly12‐29 (several males) made at Canal Point, FL on 20 Dec. 2012. It was released for cultivation on organic soils in June 2021 because of its higher stalk population, sugar yield, and economic index (profitability) than the reference check, ‘CP 96‐1252’. The cane fiber content of CP 14‐1377 (137.00 kg Mg−1) was 3% higher than that of CP 96‐1252 and 2% lower than that of ‘CP 00‐1101’ and ‘CPCL 05‐1201’. At the time of its release, CP 14‐1377 was resistant to brown rust [caused by Puccinia melanocephala (H. & P. Sydow)], orange rust [caused by Puccinia kuehnii (E.J. Butler)], smut [caused by Sporisorium scitamineum (Syd., M. Piepenbr., M. Stoll & Oberw)], mosaic (caused by Sugarcane mosaic virus strain E), and ratoon stunt disease [caused by Leifsonia xyli subsp. xyli (Evtsuhenko et al.)]. It was also moderately resistant to leaf scald [caused by Xanthomonas albilineans (Ashby, Dowson)] and Sugarcane yellow leaf virus. It had an acceptable level of freeze tolerance for Florida. CP 14‐1377 had yield and disease traits superior to the widely grown cultivar CP 96‐1252; therefore, CP 14‐1377 has the potential to positively affect sugarcane production in Florida.

Registration of ‘CP 14‐1490’ sugarcane

Abstract‘CP 14‐1490’ (Reg. no. CV‐212, PI 700785), a sugarcane (a complex hybrid of Saccharum spp) cultivar, was developed through cooperative research conducted by the USDA‐ARS, the University of Florida, and the Florida Sugar Cane League, Inc. The Florida Sugarcane Variety Committee released CP 14‐1490 in June 2021 to growers for commercial cultivation on organic (muck) soils. It originated from a cross made at Canal Point (CP) on 29 Nov. 2011, where ‘CP 04‐1844’ (PI 664935) was the female parent, and the male parent was ‘CPCL 02‐8021’. CP 14‐1490 was released for its high sugar yields; acceptable commercial recoverable sucrose (though it had significantly lower cane yield at the second ratoon); resistances to Sugarcane mosaic virus strain E (mosaic) and ratoon stunt disease (caused by Clavibacter xyli subsp. xyli Davis et al.); moderate resistances to brown [caused by Puccinia melanocephala (H. & P. Sydow)] and orange rusts [caused by Puccinia kuehnii (Kruger) E. Butler], and leaf scald [caused by Xanthomonas albilineans (Ashby) Dowson]; and moderate susceptibility to smut [caused by Sporisorium scitamineum (Syd., M. Piepenbr., M. Stoll & Oberw)]. Yield data of CP 14‐1490 and reference checks (i.e., ‘CP 00‐1101’ [PI 651881], ‘CP 96‐1252’ [PI 634935], ‘CPCL 05‐1201’ [PI 672485]) were collected from 15 harvests (i.e., three crop cycles [plant cane, first and second ratoon] at five organic‐soil locations in final‐stage replicated yield trials. There was no significant difference in cane yield with all tested reference checks and no significant difference in sugar yield with CP 00‐1101 and CPCL 05‐1201. When compared to CP 96‐1252, CP 14‐1490 had significantly (P ≤ .05) higher sucrose yield (19.2%) and commercial recoverable sucrose (5%). CP 14‐1490 rated moderately tolerant to freezing among 23 tested genotypes.

Registration of ‘CP 14‐1934’ sugarcane for Florida organic soils

Abstract‘CP 14‐1934’ (Reg. no. CV‐210, PI 700310) sugarcane cultivar, a complex hybrid of Saccharum spp., was developed through cooperative research of the USDA‐ARS, the University of Florida, and the Florida Sugarcane League. The Florida Sugarcane Variety Committee released CP 14‐1934 in June 2021 for commercial cultivation on organic (muck) soil. CP 14‐1934 originates from a cross CPX11‐1041 between CP 07‐2460 (female parent) and CP 06‐2335 (male parent). CP 14‐1934 was released due to its high cane yield; high sucrose yields; acceptable commercial recoverable sucrose; and resistance to brown rust (tested positive to Bru1 marker), orange rust, sugarcane mosaic virus strain E (mosaic), and ratoon stunting disease. CP 14‐1934 was found moderately resistant to leaf scald and to have intermediate freeze tolerance. Based on results of three harvests cycles over five locations in final‐stage replicated yield trials (Stage 4) on muck soils, CP 14‐1934 cane and sucrose yields were 17.8 and 19.8% greater than the mean of reference cultivars, respectively. CP 14‐1934 rarely flowers in Florida's climate. The new released cultivar CP 14‐1934 is expected to increase the profitability and the efficiency in the use of resources of Florida sugarcane growers.

Registration of ‘CP 13‐4474’ sugarcane for sand soils

Abstract‘CP 13‐4474’ (Reg. no. CV‐209, PI 700305) sugarcane cultivar (a complex hybrid of Saccharum spp.) was released to growers in June 2021 for cultivating on sand soils in Florida after a decade‐long advancement through cooperative research conducted by the USDA‐ARS, the Florida Sugar Cane League Inc., and the University of Florida. It originated from a poly‐cross at Canal Point (CP). The Florida Sugarcane Variety Committee released CP 13‐4474 due to its high sugar yields, sucrose content on sand soils, and acceptable disease resistance. CP 13‐4774 has demonstrated resistance to brown rust (caused by Puccinia melanocephala H. & P. Sydow), orange rust (caused by Puccinia kuehnii E.J. Butler), mosaic (caused by Sugarcane mosaic virus strain E), and ratoon stunt (caused by Leifsonia xyli subsp. xyli Evtushenko et al.) and moderate resistance to smut [caused by Sporisorium scitamineum (Syd.) M. Piepenbr. et al.], leaf scald (caused by Xanthomonas albilineans Ashby, Dowson), and yellow leaf syndrome (caused by Sugarcane yellow leaf virus). In late‐stage yield trials, CP 13‐4474 sugar yields were 9.4% greater than that of the check variety ‘CL 88‐4730’, while sucrose yields did not differ significantly from the reference check ‘CP 96‐1252’. CP 13‐4474 displayed superior resistance to both brown and orange rusts and produced more commercial recoverable sucrose than all three tested reference checks over the same harvest trials. With its demonstrated resistance to diseases and elevated sugar production capacity, CP 13‐4474 is expected to positively influence both sugarcane production and crop sustainability in Florida.

Registration of ‘CP 13‐1223’ sugarcane for Florida organic soils

Abstract‘CP 13‐1223’ (Reg. no. CV‐204, PI 698176) sugarcane (a complex hybrid of Saccharum spp.) was released to growers in June 2020 for producing on muck soils in Florida. It was developed through a decade‐long cooperative research program between the USDA‐ARS, the University of Florida Everglades Research and Education Center, and the Florida Sugar Cane League, Inc. This cultivar resulted from a poly‐cross made at the USDA‐ARS Canal Point (CP) Sugarcane Field Station. CP 13‐1223 was released because of its high commercial recoverable sucrose (CRS) and stalk weight, and demonstrated acceptable levels of cane and sucrose yields on muck soils. CP 13‐1223 has resistance to orange rust, leaf scald, Sugarcane mosaic virus strain E, ratoon stunt disease, and smut, and moderate resistance to brown rust. Based on results from 13 harvests across replicated yield trials at five locations, CP 13‐1223 performed 29.6 and 9.5% higher in CRS and stalk weight, respectively, than the check cultivar ‘CP 96‐1252’. It did not differ significantly from CP 96‐1252 in either cane yield, sucrose yield, or economic profitability. CP 13‐1223 is considered to have moderate tolerance to freezing in field tests.

Eight Species of Poaceae Are Hosting Different Genetic and Pathogenic Strains of Sugarcane Mosaic Virus in the Everglades Agricultural Area.

Sugarcane mosaic virus (SCMV) was detected by reverse transcription polymerase chain reaction in eight different species of the Poaceae family in the Everglades Agricultural Area (EAA) of south Florida: broadleaf signalgrass (Urochloa platyphylla), Columbus grass (Sorghum almum), goosegrass (Eleusine indica), maize (Zea mays), sorghum (Sorghum bicolor), St. Augustine grass (Stenotaphrum secundatum), southern crabgrass (Digitaria ciliaris), and sugarcane (Saccharum interspecific hybrids). Based on their coat protein (CP) gene sequence, 62 isolates of SCMV from Florida and 29 worldwide isolates representing the known genetic diversity of this virus were distributed into eight major phylogenetic groups. SCMV isolates infecting Columbus grass, maize, and sorghum in Florida formed a unique group, whereas virus isolates infecting sugarcane in the United States (Florida and Louisiana) clustered with isolates from other countries. Based on the entire genome coding region, SCMV isolates infecting sugarcane in Florida were closest to virus isolates infecting sorghum species or St. Augustine grass. Virus isolates from Columbus grass, St. Augustine grass, and sugarcane showed different virulence patterns after mechanical inoculation of Columbus grass, St. Augustine grass, and sugarcane plants, thus proving that these isolates were different pathogenic strains. Sugarcane was symptomless and tested negative for SCMV by tissue blot immunoassay after inoculation with crude sap from SCMV-infected Columbus grass, indicating that Columbus grass was not a reservoir for SCMV infecting sugarcane in the EAA. Close CP sequence identity between isolates of SCMV from Columbus grass, maize, and sorghum suggested that the same virus strain was naturally spreading between these three plants in south Florida.

Registration of ‘CP 13‐4100’ sugarcane

Abstract‘CP 13‐4100’ (Reg. no. CV‐202, PI 698546) sugarcane cultivar (a complex hybrid of Saccharum spp.) was developed through cooperative research conducted by the USDA‐ARS, the University of Florida, and the Florida Sugar Cane League, Inc. The Florida Sugarcane Variety Committee (FSVC) released CP 13‐4100 in June 2020 to growers for commercial cultivation on mineral (sand) soils. It originated from a polycross made at Canal Point (CP) on 3 Dec. 2008 where CP 96‐1252 was the female parent and the male parent was unknown and could be any one of genotypes used in the polycross. CP 13‐4100 was released by FSVC for its high cane and sucrose yields, acceptable commercial recoverable sucrose, and resistances to orange rust, leaf scald, Sugarcane mosaic virus strain E (mosaic), and smut, and acceptable levels of susceptibility to brown rust. CP 13‐4100 and commercial reference checks (i.e., CL 88‐4730, CP 96‐1252, CPCL 97‐2730) yield data were collected from 12 harvests (i.e. three crop cycles—plant cane, first, and second ratoon—at four sand‐soil locations) in final‐stage replicated yield trials. Compared with CL 88‐4730 and CPCL 97‐2730, CP 13‐4100 had significantly (P ≤ .0001) higher cane yield (tonnes of cane per hectare: 18.7 and 29.5%), sucrose yield (tonnes of sugar per hectare: 26.3 and 30.7%), and economic index (EI; 10.9–16.9%) and no significant differences from CP 96‐1252 in these traits. CP 13‐4100 tested negative for the Bru1 marker, which is linked to a quantitative major locus of brown rust resistance. CP 13‐4100 could be considered moderately tolerant to freezing among 23 tested genotypes.

Registration of ‘CP 11‐1640’ sugarcane

Abstract‘CP 11‐1640’ (Reg. no. CV‐199, PI 695085) sugarcane (a complex hybrid of Saccharum spp.) was developed through cooperative research conducted by the USDA–ARS, the University of Florida, and the Florida Sugar Cane League, Inc., and released by the Florida Sugarcane Variety Committee (FSVC) to growers for commercial cultivation on mineral (sand) soils in Florida in June 2019. It was selected from a polycross made at Canal Point on 2 Jan. 2009 with Canal Point sugarcane breeding line CP 01‐2390 (female parent). Its male parent was unknown and could be any one of the clones used in the polycross. CP 11‐1640 was released by FSVC because of its high cane and sucrose yields, acceptable commercial recoverable sucrose, and resistance to brown rust, orange rust, leaf scald, Sugarcane mosaic virus strain E (mosaic), and smut. Based on the results of 12 harvests with three crops (plant cane, first ratoon, and second ratoon) at four locations in final‐stage replicated yield trials on sand soils and compared with reference cultivars (CL 88‐4730, CP 96‐1252, CPCL 97‐2730), CP 11‐1640 had significantly higher cane yield (13.4–16.9%), sucrose yield (12.0–12.8%), and economic index (10.9–16.9%) than CL 88‐4730 and CPCL 97‐2730 and did not differ from CP 96‐1252 in any of these traits. Cane fiber content of CP 11‐1640 (138.9 kg Mg−1) was equivalent to that of CL 88‐4730 but slightly higher than that of CP 96‐1252 and CPCL 97‐2730. CP 11‐1640 was considered to be moderately tolerant to freezing among 18 genotypes tested.

Extensive recombination challenges the utility of Sugarcane mosaic virus phylogeny and strain typing

Sugarcane mosaic virus (SCMV) is distributed worldwide and infects three major crops: sugarcane, maize, and sorghum. The impact of SCMV is increased by its interaction with Maize chlorotic mottle virus which causes the synergistic maize disease maize lethal necrosis. Here, we characterised maize lethal necrosis-infected maize from multiple sites in East Africa, and found that SCMV was present in all thirty samples. This distribution pattern indicates that SCMV is a major partner virus in the East African maize lethal necrosis outbreak. Consistent with previous studies, our SCMV isolates were highly variable with several statistically supported recombination hot- and cold-spots across the SCMV genome. The recombination events generate conflicting phylogenetic signals from different fragments of the SCMV genome, so it is not appropriate to group SCMV genomes by simple similarity.

Registration of ‘CP 09‐4153’, ‘CPCL 09‐4160’, and ‘CP 09‐4758’ Sugarcane for Sand Soils in Florida

‘CP 09‐4153’ (Reg. no. CV‐189, PI 688442), ‘CPCL 09‐4160’ (Reg. no. CV‐188, PI 688443), and ‘CP 09‐4758’ (Reg. no. CV‐190, PI 688444) are new sugarcane (complex hybrids of Saccharum spp.) cultivars developed through cooperative research conducted by the USDA‐ARS, the University of Florida, and the Florida Sugar Cane League and released to be cultivated on mineral (sand) soils in Florida. Female and male parents, respectively are CPCL 97‐0393 and CPCL 02‐8021 for CP 09‐4153; ‘CP 80‐1743’ and Poly 01‐8 (a pollen mix) for CPCL 09‐4160; and CP 97‐2103 and CP 92‐1167 for CP 09‐4758. Averaged across three crop cycles, CP 09‐4153 and CP 09‐4758 had, respectively, 32.4 and 21.9% higher cane yield and 28.1 and 20.2% higher sucrose yield compared with ‘CL 88‐4730’, a commercial reference cultivar. CPCL 09‐4160 did not differ significantly from CL 88‐4730 in cane and sucrose yields, but it was resistant to major sugarcane diseases in the region except ratoon stunt. CP 09‐4153 and CP 09‐4758 were considered to have low to moderate freeze tolerance while CPCL 09‐4160 was considered to be moderate in freeze tolerance. Overall, these three cultivars were released by the Florida Sugarcane Variety Committee due to their high cane and sucrose yields, particularly in the ratoon crops, and their acceptable levels of resistance to brown rust, orange rust (except CP 09‐4758), smut, leaf scald (except CP 09‐4758), Sugarcane mosaic virus strain E, ratoon stunt (except CPCL 09‐4160), and Sugarcane yellow leaf virus.

Identification of Sugarcane Host Factors Interacting with the 6K2 Protein of the Sugarcane Mosaic Virus

The 6K2 protein of potyviruses plays a key role in the viral infection in plants. In the present study, the coding sequence of 6K2 was cloned from Sugarcane mosaic virus (SCMV) strain FZ1 into pBT3-STE to generate the plasmid pBT3-STE-6K2, which was used as bait to screen a cDNA library prepared from sugarcane plants infected with SCMV based on the DUALmembrane system. One hundred and fifty-seven positive colonies were screened and sequenced, and the corresponding full-length genes were cloned from sugarcane cultivar ROC22. Then, 24 genes with annotations were obtained, and the deduced proteins were classified into three groups, in which eight proteins were involved in the stress response, 12 proteins were involved in transport, and four proteins were involved in photosynthesis based on their biological functions. Of the 24 proteins, 20 proteins were verified to interact with SCMV-6K2 by yeast two-hybrid assays. The possible roles of these proteins in SCMV infection on sugarcane are analyzed and discussed. This is the first report on the interaction of SCMV-6K2 with host factors from sugarcane, and will improve knowledge on the mechanism of SCMV infection in sugarcane.

First Report of Sugarcane Mosaic Virus on Pumpkin Plants Exhibiting Mosaic and Mottling Symptoms in China

Sugarcane mosaic virus (SCMV) is responsible for economic losses in sorghum, maize, and sugarcane worldwide. Only some monocot plants are natural hosts of SCMV. In July 2017, mosaic symptoms such as irregular chlorosis and mottling were observed in the leaves of pumpkin (Cucurbita moschata) plants at Fujian Agriculture and Forestry University, Fuzhou, Fujian Province. Seven pumpkin plants with typical mosaic symptoms were tested by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) using antibodies for cucumber mosaic virus (Agdia, Elkhart, IN) and squash mosaic virus (Agdia), respectively. However, neither of these two pathogens was detected. Because the sugarcane plants growing near pumpkin plants had been confirmed to be infected by SCMV isolate FZC1 (Deng et al. 2016), we presumed that the mosaic symptoms on pumpkin plants were owing to SCMV infection. Using the SCMV-specific antibodies (Agdia), the ELISA assays showed that six of the seven pumpkin plants were infected by SCMV. To identify the strains of SCMV infecting the pumpkin plants, total RNA was extracted from leaves of all six pumpkin plants and two sugarcane plants infected by SCMV from the neighboring field using a TransZol Up Plus RNA Kit (Transgen, Beijing, China). The cDNA synthesis was performed using M4T primer (5′-GTTTTCCCAGTCACGAC[T]₁₅-3′) (Chen et al. 2001) by reverse transcription. Subsequently, polymerase chain reaction was performed using an SCMV-specific primer (SCMV7-F, 5′-ATTTATGGAGGAGTGGGAGC-3′) and M4 primer (5′-GTTTTCCCAGTCACGAC-3′) (Deng et al. 2016) with the amplification program as follows: 94°C for 4 min, followed by 35 cycles of 94°C for 30 s, 55°C for 30 s, and 72°C 2 min, with a final extra 7 min at 72°C. The expected 1,925-bp amplicons were produced from all eight samples. The amplicons were cloned into a pMD19-T Vector System (Takara, Dalian, China) and sequenced. The sequences of the two amplicons from sugarcane plants were identical to the corresponding fragment of SCMV isolate FZC1. The sequences of the six amplicons from pumpkin plants were identical and were subjected to BLASTn search in GenBank. The results showed that the query sequence (GenBank: MK680822) had the highest nucleotide similarity, 95.97%, and the highest amino acid identity of 99.04% with SCMV isolate FZC1 (GenBank: KR108212) Phylogenetic analysis based on the SCMV coat protein showed that the pumpkin SCMV isolate was clustered into the same subgroup with FZC1. We prepared inoculum by homogenizing approximately 1 g of symptomatic leaves of SCMV-infected sugarcane plants grown in the vicinity of pumpkins in 3 ml of 0.01 M phosphate buffer (pH 7.0). Then healthy pumpkin plants (cv. BeiBei) were mechanically inoculated with the inoculum and cultured in the greenhouse under the following conditions: photoperiod 14-h light/10-h dark, light intensity 600 μmol/m²/s, temperature regime 30°C day/25°C night. Three weeks later, 7 out of 10 inoculated pumpkin plants developed mosaic symptoms, and the DAS-ELISA assays confirmed presence of SCMV in symptomatic pumpkin leaves. To our knowledge, this is the first report of SCMV infection of pumpkins and disease symptoms of this virus on a dicotyledonous plant. These findings will benefit the epidemiology and management of SCMV in China.

Registration of ‘CP 08‐1968’ Sugarcane

‘CP 08‐1968’ (Reg. No. CV‐185; PI 687332) sugarcane (a complex hybrid of Saccharum spp.) cultivar was developed through cooperative research conducted by the USDA‐ARS, the University of Florida, and the Florida Sugarcane League, Inc. At the 5 June 2017 Florida Sugarcane Variety Committee Meeting, CP 08‐1968 was released to growers for all soils in Texas; seedcane became available in September 2018. At the 30 Oct. 2017 Florida Sugarcane Variety Committee Meeting, CP 08‐1968 was approved as a co‐release to growers with sand soils in Florida and all soils in Texas. CP 08‐1968 was selected from a biparental cross of CP 01‐1178 × CP 00‐1301 made at Canal Point, FL, in November 2006. The female parent, CP 01‐1178, and the male parent, CP 00‐1301, are not commercial cultivars. Cane yield of CP 08‐1968 on sand soils in Florida, averaged across nine harvests through three crop cycles (plant‐cane, first‐ratoon, and second‐ratoon), was 15.0 and 10.1% higher (P < 0.1) than that of CL 88‐4730, a commercial check for sand soils, and CP 89‐2143, a high commercial recoverable sucrose (CRS) commercial check for muck and sand soils. Although CP 08‐1968 had 2.8 and 6.0% lower CRS than CL 88‐4730 and CP 89‐2143, respectively (Glaz et al., 2000), high cane yield resulted in 11.3 and 2.1% higher (P < 0.1) sucrose yield than CL 88‐4730 and CP 89‐2143, respectively. CP 08‐1968 was released because of its high cane and sucrose yields on sand soils, as well as its acceptable levels of resistance to brown rust, smut, Sugarcane mosaic virus strain E (mosaic), Sugarcane yellow leaf virus (Comstock et al., 1999), and ratoon stunt. CP 08‐1968 is susceptible to orange rust and has moderate to good freeze tolerance. CP 08‐1968 tested negative for the Bru1 quantitative trait locus, which is an indicator of brown rust resistance.

Registration of ‘CP 09‐2392’ Sugarcane

‘CP 09‐2392’ (Reg. No. CV‐182; PI 688299) sugarcane, a complex hybrid of Saccharum spp., was developed through cooperative research conducted by the USDA–ARS, the University of Florida, and the Florida Sugarcane League, Inc., and was released to growers in June 2016. CP 09‐2392 was selected from a cross made at the USDA–ARS Sugarcane Field Station in Canal Point, FL, in December 2007. The female parent was ‘CP 01‐2390’; the identity of the male parent is difficult to determine as the cross included multiple potential male parents, i.e., a polycross. CP 09‐2392 was superior to the reference cultivar ‘CL 88‐4730’ on sand soils with regard to stalk weight, cane yield, commercial recoverable sucrose (a measure of sucrose content), sucrose yield, and economic index (i.e., overall profitability). CP 09‐2392 is resistant to brown rust, leaf scald, ratoon stunt, Sugarcane mosaic virus strain E (mosaic), smut, and Sugarcane yellow leaf virus and is moderately resistant to orange rust. In addition, CP 09‐2392 has good freeze tolerance. This cultivar is recommended for mineral (sand) soils in Florida.

Registration of ‘CP 10‐1208’ Sugarcane

‘CP 10‐1208’ (Reg. No. CV‐183, PI 688293) sugarcane (a complex hybrid of Saccharum spp.) was developed through cooperative research conducted by the USDA–ARS, the University of Florida, and the Florida Sugar Cane League, Inc., and released to growers for commercial use on mineral (sand) soils in Florida in June 2017. It was selected from a biparental cross made at Canal Point (CP) on 21 Dec. 2007 with the CP sugarcane breeding lines CP 01‐2390 (female parent) and TCP 98‐4454 (male parent). CP 10‐1208 was released by the Florida sugarcane variety committee because of its high cane and sucrose yields and acceptable commercial recoverable sucrose on sand soils, as well as its acceptable levels of resistance to brown rust, leaf scald, Sugarcane mosaic virus strain E (mosaic), and smut. Based on results of nine harvests with three crops (plant cane, first ratoon, and second ratoon) at three locations in final‐stage replicated yield trials on sand soils and compared with two reference cultivars (‘CP 96‐1252’ and ‘CL 88‐4730’), CP 10‐1208 had 27.9 and 32.6% higher cane and sucrose yields than CL 88‐4730 but did not differ from CP 96‐1252 in either cane yield or sucrose yield. Fiber concentration of CP 10‐1208 was 108.7 g kg−1 of cane. CP 10‐1208 ranked 12th (plant cane) to 8th (first ratoon) for freeze tolerance among 23 genotypes tested.

Registration of ‘CP 09‐1952’ Sugarcane

‘CP 09‐1952’ (Reg. No. CV‐179, PI 686942) sugarcane (a complex hybrid of Saccharum spp.) was developed through cooperative research conducted by the USDA–ARS, the University of Florida, and the Florida Sugarcane League, Inc. At the 6 June 2016 Florida Sugarcane Variety Committee Meeting, CP 09‐1952 was released to growers for organic (muck) soils in Florida, and seed cane was made available in September 2016. CP 09‐1952 was selected from a polycross of CP 01‐2390 × Poly 06‐30 made at Canal Point, FL, in January 2007. The female parent, CP 01‐2390, is not a commercial cultivar. The male parent is unknown, as it is one of 15 clones comprising the polycross. Cane yield of CP 09‐1952 on muck soils, averaged across 19 harvests through three crop cycles (plant cane, first ratoon, and second ratoon), was 30.1% higher (P < 0.1) than that of ‘CP 89‐2143’, a high recoverable sugar commercial check for muck soils. The commercial recoverable sucrose for CP 09‐1952 was not significantly higher than the check, but high cane yield resulted in 30.3% higher (P < 0.1) sucrose yield than CP 89‐2143. CP 09‐1952 was released because of its high cane and sucrose yields on muck soils and its acceptable levels of resistance to orange rust, leaf scald, Sugarcane mosaic virus strain E, Sugarcane yellow leaf virus, and ratoon stunt. CP 09‐1952 is moderately susceptible to brown rust, and it has moderate to low freeze tolerance. CP 09‐1952 tested negative for the Bru1 quantitative trait loci, which is an indicator of brown rust resistance.

Registration of ‘CP 09‐1822’ Sugarcane

‘CP 09‐1822’ (Reg. No. CV‐180; PI 686956) sugarcane (a complex hybrid of Saccharum spp.) was released in June 2016 for commercial cultivation on sand (mineral) soils in Florida. This cultivar was developed through a collaborative sugarcane cultivar development program of the USDA–ARS, the University of Florida, and the Florida Sugarcane League, Inc., based at Canal Point (CP), Florida. The parentage of CP 09‐1822 is CP 01‐2459 × CPCL 02‐8021. CP 09‐1822 had significantly greater mean stalk weight, tonnes of cane per hectare, tonnes of sugar per hectare, and economic index than the reference cultivars, ‘CL 88‐4730’, ‘CP 78‐1628’, and ‘CP 89‐2143’, in nine harvests with three crops (plant cane, first ratoon, second ratoon) at each of the three locations. Mean economic index or profitability of CP 09‐1822 was 21% higher than the second most common cultivar on sand soil, CL 88‐4730, and 36% higher than the other two reference cultivars. CP 09‐1822 is considered resistant to brown rust, orange rust, Sugarcane mosaic virus strain E, and Sugarcane yellow leaf virus, is moderately resistant to leaf scald and ratoon stunting disease, and is moderately susceptible to smut. CP 09‐1822 has the Bru1 gene that provides resistance against brown rust. CP 09‐1822 ranked 9 among 32 tested genotypes for post‐freeze temporal sucrose deterioration and showed moderate to high freeze tolerance.