Although agriculture is the business of converting solar energy into food and fiber, there has been little use of solar radiation data in regression models of weather and crop growth. A major problem in these studies is the rapidly increasing plant size and growth potential under similar environmental conditions. This has led to the use of standardized measures of Crop Growth Rate (CGR), such as Relative Growth Rate (RGR) and Net Assimilation Rate (NAR), which often overcorrect for crop size. Rather than correct CGR for crop size in the present work solar radiation is weighted to estimate the amount of solar energy intercepted by a corn canopy. Another challenge in solar radiation‐crop growth studies to assess the interaction of solar radiation and plant moisture stress, and this factor is also examined. Weather and corn (zea mays L.) growth measurements in the field at West Lafayette, In., from 1969 to 1971, were used to assess different methods of handling solar radiation in corn growth regression models. Daily solar radiation (S) was weighted with a leaf area function, f(LAI), using Boguer's law and an extinction coefficient determined by K. R. Stevenson and J. W. Tanner to obtain the intercepted solar radiation, SI = S(1 — exp(−0.79 LAI)). This variable was better correlated with total aboveground corn plant growth rates than was either f(LAI) or S. SI was divided by pan (Epan) or Piche evaporation (EPiche), or their square roots, to obtain a derived variable which identified not only the solar energy intercepted by the corn canopy, but also a consideration of atmospheric conditions causing plant moisture stress limitations upon energy conversion within the corn plant. The single variable, SI‐E‐−Piche, was associated with about 45% of the variance in above ground plant growth rates and about 25% of the variability in grain growth rates during the 1969–1971 seasons. The derived variables were tested with 1972 weather and corn growth data and also by pooling data for the eight seasons into three other periods, 1969–1970, 1971–1972, and 1969–1972. The single derived variables, SI‐E½Piche, was associated with 72% of the short period plant growth rate variance in the 1969–1970 period and about 27% in the 1971–1972 period, but it explained practically none of the variability in 1971–1972 grain growth.

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Little information is available on the amounts of net radiation utilized by different populations of corn (Zea mays L.). To increase the range in corn microenvironments for a weather and corn growth study, we used two planting dates and two populations in 1970 at West Lafayette, Ind. The soil was Chalmers silt loam. Soil moisture in the top meter remained above 60% available throughout the season. Net radiation was measured 1 m above two corn populations of 42,000 (42K) and 62,000 (62K) plants/ha within an early and a late planting. Pairs of Fritschen‐type net radiometers were exposed from a permanent mast within each of the four microenvironments. Replication was with two portable masts moved every week to alternate temporary locations in each population. Differences between net radiation measured within the same population at the permanent and temporary mast locations generally were larger than those between the permanent mast locations in the 42K and 62K populations. For the incompletely replicated experiment, we used a difference of differences t‐test to determine that there were no significant differences (α level 0.20) between net radiation measured over the 62K and 42K populations. Sources of experimental error discussed are instrumental calibration, field measurements of net radiation, possible canopy wear associated with the temporary mast movement, and nonhomogeneous crop canopies, especially with the net radiometers exposed ≤ 1 m above the crop. Without adequate replication interpreting environmental measurements risky, especially in row crops.

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Bananas (Musa spp.) are a popular ornamental plant in the southern United States; however, only a few cultivars, such as Lady's Finger and Orinoco, are grown in Georgia. Thirty-three primarily commercial cultivars of bananas were grown for 2 years near Savannah, Georgia, to determine their suitability for ornamental and nursery production, and for 3 years for fruit observations. Most plants were grown from tissue culture plugs. They were given rates of fertilization used for commercial banana fruit production. Most cultivars produced 10 to 14 leaves and grew to heights of 1.5 to 2.0 m. Some displayed desirable ornamental characteristics such as pink-tinted pseudostems, colorful flowers, and large graceful leaves. Some of the most attractive tall-growing cultivars were Belle, Ice Cream, Kandarian, Manzano, Saba, and 1780. Some of the most attractive medium-height cultivars were Dwarf Namwah, Dwarf Orinoco, Goldfinger, Raja Puri, and Super Plantain. In the short category, the cultivars Dwarf Nino, Gran Nain, Kru, and Sum X Cross were among the most attractive ornamentals. Many of the cultivars flowered and began producing fruit in late summer, although only ‘Raja Puri’, ‘Sweetheart’, and ‘1780’ produced palatable fruit before frost in November. Cultivars were also rated for their ability to produce suckers that could be used for nursery production. In year 2, ‘Manzano’ and ‘1780’ produced more than six high-quality suckers for nursery propagation. Potential income for these cultivars was over $60 per plant. For the planting as a whole, sales of suckers at a field day averaged $7 per plant in year 2, and $17 per plant in year 3.