Cenicaña identified four varieties from the germplasm bank with biomass production qualities due to their efficient use of nitrogen. The results were obtained in greenhouses, in hydroponic crops, where the response of 290 genotypes to nutrient supply was evaluated in treatments with high and low nitrogen availability.
Writers: Fernando S. Aguilar1, Carolina Saavedra-Diaz1,2, John Henry Trujillo-Montenegro1, Alejandra Londono1, Hugo Arley Jaimes1, John Jaime Riascos1, Jershon Lopez1, Luis Fernando Chavez1, and Fernando Munoz1
The Colombian varieties ICA 75-1 and CC 87-832, the Brazilian SP 79-1184 and the Australian Q 67, were highlighted in the experimentation that seeks elite parents of genetic improvement to contribute to the efficient use of nitrogen in the cultivation areas.
The efficient use of nitrogen (UEN) of a genotype is defined as its capacity to produce a higher biomass content, which distinguishes it from the rest -in dry weight-, for each unit of nitrogen stored in the tissue (Robinson et al. 2007).
To identify the possible parents, between 2019 and 2022, the genetic variability of 290 varieties of the sugarcane germplasm bank was characterized with respect to the UEN, in hydroponic crops maintained in Hoagland solution.
The solution contained all the major and minor elements necessary for plant development, except nitrogen (N), which was supplied in the form of ammonium nitrate (NH4DO NOT3), in two amounts (millimolar, mM): low N = 4 mM and high N = 14 mM.
Three months after sowing, in five replicates per variety, the dry weight of the aerial biomass of the plants was measured, as well as the concentration of nitrogen in the plant tissue, the latter using near-infrared spectroscopy or NIR.
Finally, the UEN of each variety was determined (g/g, proportion of biomass with respect to the N content in the tissue) and the genetic variability of the varieties was measured with reference to the UEN.
What are we looking for?
- Characterize the genetic variability of the sugarcane germplasm bank regarding the efficient use of nitrogen (UEN).
- Select superior varieties in the UEN, even in conditions of low nutrient supply.
- Assist the improvement of cane with genotypes characterized by their genetic potential in the UEN, which are integrated as parents in elite groups of crosses with specific purposes and according to the Cenicaña scheme.
- Contribute to the sustainability of the crop, maintaining productivity without increasing the carbon footprint.
- Implement fast and reliable methodologies that facilitate research in applied omic sciences in agriculture.
Nitrogen is a fundamental part of chlorophyll, a necessary component for the plant to use solar energy for growth and development during photosynthesis (Leghari et al. 2016). Therefore, higher nitrogen supplies in the crop cycle are associated with higher biomass production in plants. Our results showed that:
- The biomass production of 290 evaluated varieties was nearly double (8.76 ± 4.03 g) in the high N treatment compared to the biomass (4.36 ± 2.08 g) in the low N treatment.
- The genetic variability in terms of biomass was greater with high N, between 0.9 and 21.4 g, than that observed with low N (Figure 1).
- The ICA 75-1 variety had the highest biomass in both N treatments. This variety was produced by the Instituto Colombiano Agropecuario (ICA), a sugarcane breeding program in Palmira (Cassalett Davila and Rangel Jimenez 1995), and It is currently maintained as a source of adaptation genes of agronomic importance.
Of the 209 varieties evaluated, 18 produced high biomass in both N treatments (Figure 2). This indicates that there was no differential response between them due to the N content added to the substrate.
Figure 1. Distribution of 290 sugarcane varieties in hydroponic cultivation according to the average dry aerial biomass production in two NH supply treatments4DO NOT3: low N (4 mM) and high N (14 mM).
Figure 2. Dry aerial biomass production of 290 sugarcane varieties in hydroponic cultivation, in two NH supply treatments4DO NOT3: low N (4 mM) and high N (14 mM). The dotted lines indicate the value of the mean biomass plus 1.5 times the standard deviation for high N (14.8 g) and for low N (7.5 g). The genotypes with high biomass production common in both N levels are marked with numbers from 1 to 18. The genotype with the lowest production is marked with B, in red.
Efficient use of nitrogen
The previous analysis indicated that the higher the N supply, the higher the biomass content. However, when the UEN of the varieties is observed, that is, the biomass produced in relation to the N content in the plants, the picture is different. With the UEN it was possible to observe that:
- The evaluated varieties presented a higher UEN under low N conditions, equivalent to 71.83 ± 15.24 g of biomass per gram of N in the tissue.
- When analyzing within each nitrogen level, it was observed that the difference between the varieties with the lowest and highest UEN varied 2.8 times within the low N treatment and 3.1 times in the high N treatment (Figure 3).
- Seven varieties accumulated more than 69 g of dry biomass for each gram of N in the tissue, regardless of the N supply treatment (Figure 3), so they are considered stable with respect to the UEN.
- Of the seven varieties, four varieties exceeded 105 g of biomass per gram of nitrogen in the low N treatment and were selected as potential parents.
Figure 3. Efficient use of nitrogen (UEN) of 290 sugarcane varieties in hydroponic cultivation, in two NH supply treatments4DO NOT3: low N (4 mM) and high N (14 mM). The dotted lines indicate the value of the UEN mean plus 1.5 times the standard deviation with high N (69.67 g/g) and with low N (94.69 g/g). Green dots show the varieties with high UEN in both conditions, while in red is the one with the lowest UEN.
- A high genetic diversity was evidenced among the sugarcane varieties in relation to the efficient use of nitrogen. This indicates the existence of varieties with the capacity to produce higher biomass per unit of N in the tissues.
- The varieties CC 87-832, ICA 75-1, SP 79-1184 and Q 67 were the most outstanding in the UEN in both N treatments (high and low). ICA 75-1, in particular, was second in UEN (>105 g/g) and first in biomass (10.72 g) with low N.
- These varieties are considered promising as parents in the sugarcane genetic improvement program in Colombia.
(Robinson et al. 2007)
Cassalett Davila, C., and Rangel Jimenez, H. 1995. Genetic Improvement. In The cultivation of cane in the sugar zone of Colombia.
Leghari, SJ, Wahocho, NA, Laghari, GM, HafeezLaghari, A., MustafaBhabhan, G., HussainTalpur, K., Bhutto, TA, Wahocho, SA, and Lashari, AA 2016. Role of nitrogen for plant growth and development: A review. Advances in Environmental Biology 10(9): 209-219.
Robinson, N., Fletcher, A., Whan, A., Critchley, C., von Wirén, N., Lakshmanan, P., and Schmidt, S. 2007. Sugarcane genotypes differ in internal nitrogen use efficiency. Functional Plant Biology 34(12): 1122-1129.
1 Sugar Cane Research Center, Cenicaña
2 Pontifical Javeriana University, Cali