Harvest index

Some modern varieties of cereals such as wheat and rice achieve high yield potential through genetic factors for plant dwarfness that improve harvest index. A popular notion among plant breeders is that high-yielding... 

Fig. 8.6 The relationship between initial SOC and the net C balance (stover + roots - maintenance requirement), and relative amount of carbon supplied by the roots (maintenance requirement -root biomass carbon) tilled and no-tilled system. Calculations were based on tilled and no-tilled systems with maintenance requirements of 16% and 10% of the SOC, a 11,270 kg grain ha-1 (180 bu acre-1), a harvest index of 0.5, a root to shoot ratio of 0.55, and that non-harvested com stover contained 0.4 g carbon(g plant)-1...

The impact of the root to shoot ratios on calculated maintenance requirements is important because root to shoot ratios are highly variable and almost always underestimate below-ground biomass. Amos and Walters (2006) reported that the net below-ground C deposition in com at physiological maturity was 29% 13% of the shoot biomass (leaves, stems, and husks) in 41 studies. The use of these values is further complicated by the use of different definitions for root to shoot ratio. Converting Amos and Walters (2006) units to units used by Johnson et al. (2006) would reduce the reported values from 0.29 to 0.15 (harvest index 50%). 

Wheeler, R. M. (2003). Carbon balance in bioregenerative life support systems Effects of system closure, waste management, and crop harvest index. Adv. Space Res., 3J(1), 169-175. 

It requires a far greater investment in a nonrecyclable aerial canopy at the expense of tuber yield. This differential is readily apparent when contrasting the harvest index between chicory roots and Jerusalem artichoke tubers (e.g., Schittenhelm, 1999). 

Elemental Concentration and Harvest Index of Jerusalem Artichoke Tubers... 

Harvest index (HI) (Mass of the plant part of interest/plant mass) x 100 -64-78% McLaurin et al., 1999 Schittenhelm, 1996 Baldini et al., 2003... 

The harvest index is the ratio between economic yield and biological yield. It is usually determined by the weight of the economic component in relation to the total plant weight, and therefore gives an indication of the relative distribution of assimilates between the tubers and the... 

In the cultivar Sunchoke, grown in southeastern U.S., the harvest index reached 0.70 by the end of the growing season, with a tuber yield of 14.6 t haA High harvest indexes and tuber yields are dependent on the efficient reallocation of dry matter from aboveground into subterranean plant parts. The Sunchoke study suggested that yield could potentially be improved through earlier tuber induction and development (McLaurin et al., 1999). 

Anon., Harvest index criterion for selecting for high yield ability, in Annual Report of the International Rice Research Institute for 1977, International Rice Research Institute, Los Banos, The Philippines, 1978, pp. 21-25. 

Enhanced "harvest index" Improved standing ability Improved light interception Improved shoot/root ratio... 

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