Origin

Organic ‘TAMC 101’ originated from a single plant selection from the extremely variable PI 293587 introduced in the United States in 1963. The origin of this PI is unknown. A single plant with a significant aboveground biomass production was noted from PI 293587. Seeds of the selected single plant were increased in the organic plot at the Texas A&M AgriLife Research and Extension (Vernon, TX, USA) and stored at the Texas A&M AgriLife Foundation Seed Service.

Description

Organic ‘TAMC 101’ has a semiprostrate growth habit, with purple flowers. It has a globose-shaped seed with a smooth, brown seedcoat and a cream eye. It has green hypocotyls and a strong main stem. The leaves are an intermediate green, with an intermediate texture (Fig. 1). The plants covered the soil surface rapidly compared with the check used in our study. This assisted with weed control and suppression in our organic farming system. Field trials of organic ‘TAMC 101’ were conducted from 2021–23 on organic plots in two locations: the Texas A&M AgriLife Research and Extension, and on farmers’ collaborator organic plots in Lubbock, TX, USA. At each location, the experimental unit was defined as a four-row plot that was 10 m long, with a 1 m row spacing and a 10 cm plant spacing within each row. Weeds were removed mechanically using a cultivator sweep. Dry matter (DM) yield was calculated by harvesting plants from the two middle rows from each experimental unit. A 500 g aboveground biomass sample from the two outside rows of each experimental unit was ground using a Thomas-Wiley Laboratory Mill Model 4 grinder (Arthur H. Thomas Co, Philadelphia, PA, USA) and was screened to pass through a 2 mm sieve. Ground biomass samples were sent to the Texas A&M AgriLife Extension Service Soil, Water, and Forage Testing Laboratory (College Station, TX, USA) for total N analysis. The 500 g aboveground biomass sample from the two outside rows of each experimental unit was also used for forage quality analysis, which consisted of determining crude protein (CP), acid detergent fiber (ADF), and neutral detergent fiber (NDF). Forage analysis was conducted using a DA 7250 analyzer (PerkinElmer Health Sciences Canada Inc, Winnipeg, Manitoba, Canada). Data were analyzed using analysis of variance and were run in JMP Genomics^® v. 7 (SAS Institute, Inc, Cary, NC, USA). Mean separation analysis was conducted using Fisher’s protected least significant difference at α = 0.05, and data were also run in JMP Genomics^® v (SAS Institute, Inc).

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Table 1 shows the agronomic performance of both ‘TAMC 101’ and the ‘Iron & Clay’ check across locations and throughout the years of the study. These agronomic characteristics consist of DM, aboveground N accumulation (ANA), CP, ADF, and NDF. For the combined DM across locations and over years, DM of ‘TAMC 101’ (4315 kg·ha^–1) was significantly greater than the DM of the ‘Iron & Clay’ check (3906 kg·ha^–1). For both varieties, the highest DM values were recorded during the 2022 season in Vernon, TX, USA, where the DM of ‘TAMC 101’ and the ‘Iron & Clay’ check were 6481 and 5343 kg·ha^–1, respectively. The lowest DM values were recorded for the 2021 season in Lubbock, TX, USA, where the DM of ‘TAMC 101’ and the ‘Iron & Clay’ check were 3432 and 2784 kg·ha^–1, respectively. For all location–year–environment combinations, the DM of ‘TAMC 101’ was significantly greater than DM of the ‘Iron & Clay’ check.

Table 1. Agronomic characteristics of organic ‘TAMC 101’ and ‘Iron & Clay’ cowpea in field trials from 2021–23.

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The ANA of ‘TAMC 101’ (83.4 kg·ha^–1) was significantly greater than the ANA of the ‘Iron & Clay’ check (78.6 kg·ha^–1). The highest ANA values were recorded during the 2022 season in Vernon, TX, USA, where the ANA of ‘TAMC 101’ and the ‘Iron & Clay’ check were 97.9 and 82.3 kg·ha^–1, respectively. The lowest ANA values was recorded for the 2021 season in Lubbock, TX, USA, where the ANA of ‘TAMC 101’ and the ‘Iron & Clay’ check were 71.3 and 63.5 kg·ha^–1, respectively.

The average amount of CP of ‘TAMC 101’ (22.1%) was not significantly different from the CP amount of the ‘Iron & Clay’ check (22.2%). Overall, the amount of CP varied from 20.1% to 24.5%, depending on location and year. However, the CP of both varieties was not significantly different regardless of the location–year–environment combination. These results indicate that ‘TAMC 101’ can be as competitive as the ‘Iron & Clay’ check in terms of CP.

The average amount of ADF of ‘TAMC 101’ (33.8%) was not significantly different from that of the ‘Iron & Clay’ check (34.1%). The ADF varied from 30.5% to 39.5%, depending on location and year. The average NDF of ‘TAMC 101’ (38.5%) was not significantly different from that of ‘Iron & Clay’ check (38.9%). The NDF varied from 32.7% to 43.5%.

Availability

Prospective licensees’ requests should be addressed to Richard Vierling via richard.vierling@ag.tamu.edu.