Characterizing the diversity of sweetpotato through growth parameters and leaf traits: Precocity and light use efficiency as important ordination factors

Radiation Interception, Conversion and Partitioning Efficiency in Potato Landraces: How Far Are We from the Optimum?

“…Since PAR int is determined by the aboveground biomass development, those accessions with reduced canopy cover and accelerated senescence rate presented low PAR int values, and therefore, low ε i values. There was a good correlation between tu and ε p (r Pearson = −0.62) in accordance with some studies [6,26,52], i.e., a low tu corresponded to a precocious earlier cultivar with high harvest index and also the best yields. Most of those with higher tu-late-maturing cultivar-developed more aboveground biomass than tubers, which gave them the lowest harvest index (HI) [57], and may appear to have low efficiencies due to greater respiration rate and physical loss of leaves than that of tubers [55].…”

“…The highest efficiencies obtained for potato genotypes in this study ( Table 5 ) were: (i) = 60.3% corresponding to 0.77 of the theoretical maximum for major crops (90%—[ 4 ]); (ii) = 6.4% corresponding to 0.68 of the theoretical maximum for C3 plants (9.4%—[ 30 ]); (iii) = 87%, near 0.97 of the highest theoretical estimated for tuber crops (90%—[ 31 ]). Table 5 , also contains the maximum efficiency values , and reported in the literature for C4 [ 32 , 33 , 34 , 35 , 36 , 37 , 38 ] and C3 [ 18 , 26 , 30 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ] crops.…”

“…Moreover, TY was also positively correlated with and ( Table 3 ), attesting that the combination of these efficiencies influence yield [ 4 , 12 , 30 , 53 ]. There was also a strong influence of early maturity, i.e., low –achieving maximum tuber growth early before other groups [ 26 ], and the delay of senescence—high NDVI —[ 21 ] on TY (see Equation ( 1 )). Senescence delay allows higher accumulation of intercepted radiation and its transformation into biomass, thus explaining the reported positive relation between senescence duration and dry tuber yield [ 24 , 63 ].…”

“…The slope of the decline of NDVI from its maximum value along the time, fitted by a linear function (NDVI ), was used as indicator of senescence delay (higher values means longer senescence delay) [ 22 , 23 ]. The tuberization precocity proxy was represented by [ 26 ]—parameter from the Gompertz function, modeled by SOLANUM that indicates the time when the maximum tuber partitioning rate occurred (see Condori et al [ 7 ] for further details). Higher values in means lower tuberization precocity i.e., late-maturing cultivar.…”

“…Therefore, it is a desired trait in breeding programs because it is generally associated with an extension of photosynthetic activity [ 25 ]. Senescence delay (normalized difference vegetation index (NDVI) ) is related to precocity or earliness (tuber initiation delay) which can be simulated in potato and sweetpotato as the thermal time at maximum tuber growth rate ( ) [ 24 , 26 ]. Thus, plants with low precocity show a delay in senescence, which extends the time of carbon assimilation and allocation to the tubers, ultimately obtaining higher yield.…”